JP2020132490A - Binder composition for ceramic molding, composition for ceramic molding, and ceramic green sheet - Google Patents

Abstract

To provide a binder composition for ceramic molding capable of preparing a slurry having excellent dispersibility of ceramic powder and capable of temporally holding its excellent dispersibility, when used in preparation of a slurry containing ceramic powder and a solvent.SOLUTION: A binder composition for molding ceramic that includes a (meth)acrylic copolymer A that contains a constitutional unit derived from a (meth)acrylic acid alkyl ester monomer and a constitutional unit derived from a carboxy group-containing monomer, and, having an acid value of exceeding 0 mgKOH/g and 85 mgKOH/g or less, a (meth)acrylic copolymer B containing a constitutional unit derived from (meth)acrylic acid alkyl ester monomer and a constitutional unit derived from a hydroxy group-containing monomer, having a hydroxy value of exceeding 0 mgKOH/g and 50 mgKOH/g or less, and Mw smaller than the Mw of the copolymer A, in which a content ratio of the copolymer A relative to the copolymer B is, by mass basis, 50/50 to 95/5 and its application.SELECTED DRAWING: None

Description

The present invention relates to a binder composition for ceramic molding, a composition for ceramic molding, and a ceramic green sheet.

Generally, a ceramic substrate is manufactured by firing a green sheet. The green sheet is usually composed of a ceramic powder and a binder. As the binder, a composition containing a (meth) acrylic polymer is often used.

For example, Patent Document 1 contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer, has a weight average molecular weight of 100,000 or more, and has a glass transition temperature of 0 ° C. or more (meth) acrylic. The system polymer A and the (meth) acrylic oligomer B having a weight average molecular weight of 1,000 to 30,000 are contained, and the glass transition temperature of the (meth) acrylic polymer A is the (meth) acrylic system. A binder composition for ceramic molding, which is higher than the glass transition temperature of oligomer B, is disclosed.
Further, Patent Document 2 describes (A) a carboxy group-containing vinyl monomer, (B) a hydroxy group-containing vinyl monomer, (C) an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, and (D). A molding binder polymer comprising a sintering step, comprising a copolymer of a monomer composition containing a (meth) acrylic acid ester-based monomer having a polyoxyethylene structure and / or a salt thereof, is disclosed.

Japanese Unexamined Patent Publication No. 2015-202987 Japanese Unexamined Patent Publication No. 2011-225702

A green sheet is prepared by preparing a slurry containing a ceramic powder, a binder, and a solvent, and then applying the prepared slurry onto a support using a comma coater (registered trademark) and drying the slurry. ing.
The period from the preparation of the slurry to the coating (so-called storage period of the slurry) is, for example, about 24 hours to 2 weeks. If the storage period of the slurry is long, the dispersibility of the slurry is lowered, and the components contained in the slurry may be separated or precipitated. The green sheet obtained by coating the slurry in which the components are separated or precipitated tends to have uneven thickness, and the dimensional stability of the ceramic substrate obtained by firing the green sheet tends to be poor.

Regarding the above points, both the slurry containing the ceramic molding binder composition described in Patent Document 1 and the slurry containing the molding binder polymer described in Patent Document 2 have room for improvement in dispersion stability during storage. It is believed that there is.

The problem to be solved by the present invention is that when used for producing a slurry containing a ceramic powder and a solvent, it is possible to produce a slurry having excellent dispersibility of the ceramic powder and capable of maintaining the excellent dispersibility over time. The present invention provides a ceramic molding binder composition, a ceramic molding composition, and a ceramic green sheet.

Specific means for solving the problem include the following aspects.
<1> Containing a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a carboxy group, and having an acid value of more than 0 mgKOH / g and 85 mgKOH / g or less. With a certain (meth) acrylic copolymer A,
It contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a hydroxyl group, and has a hydroxyl value of more than 0 mgKOH / g and 50 mgKOH / g or less, and has a weight average. The (meth) acrylic copolymer B having a molecular weight smaller than the weight average molecular weight of the (meth) acrylic copolymer A is included.
A binder composition for ceramic molding in which the content ratio of the (meth) acrylic copolymer A to the (meth) acrylic copolymer B is 50/50 to 95/5 on a mass basis.
<2> The binder composition for ceramic molding according to <1>, wherein the weight average molecular weight of the (meth) acrylic copolymer A is 250,000 or more and 1.5 million or less.
<3> The binder composition for ceramic molding according to <1> or <2>, wherein the weight average molecular weight of the (meth) acrylic copolymer B is 10,000 or more and less than 250,000.
<4> The binder composition for ceramic molding according to any one of <1> to <3>, wherein the glass transition temperature of the (meth) acrylic copolymer A is 0 ° C. or higher and 40 ° C. or lower.
<5> The binder composition for ceramic molding according to any one of <1> to <4>, wherein the glass transition temperature of the (meth) acrylic copolymer B is −20 ° C. or higher and 15 ° C. or lower.
<6> A ceramic molding composition containing the binder composition for ceramic molding according to any one of <1> to <5>, a ceramic powder, and a solvent.
<7> A ceramic green sheet containing the binder composition for ceramic molding according to any one of <1> to <5> and a ceramic powder.

According to the present invention, when used for producing a slurry containing a ceramic powder and a solvent, a ceramic molding binder capable of producing a slurry having excellent dispersibility of the ceramic powder and capable of maintaining the excellent dispersibility over time. Compositions, ceramic molding compositions, and ceramic green sheets are provided.

Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within the scope of the object of the present invention.

The numerical range indicated by using "~" in the present specification means a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively.
In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. .. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
In the present specification, a combination of two or more preferred embodiments is a more preferred embodiment.
In the present specification, the amount of each component means the total amount of a plurality of kinds of substances when a plurality of kinds of substances corresponding to each component are present, unless otherwise specified.

In the present specification, the "(meth) acrylic copolymer" means that the content of the structural unit derived from the monomer having a (meth) acryloyl group is the total structural unit (that is, the (meth) acrylic copolymer). It means a copolymer which is 50% by mass or more of the total constituent unit of the coalescence).

In the present specification, "(meth) acrylic" is a term that includes both "acrylic" and "methacrylic", and "(meth) acrylate" is a term that includes both "acrylate" and "methacrylate". , "(Meta) acryloyl" is a term that includes both "acryloyl" and "methacrylic".

In the present specification, "n-" means normal, "i-" means iso, "s-" means secondary, and "t-" means tertiary.

[Binder composition for ceramic molding]
The binder composition for ceramic molding of the present invention (hereinafter, also simply referred to as “binder composition”) is derived from a constituent unit derived from a (meth) acrylic acid alkyl ester monomer and a monomer having a carboxy group. A (meth) acrylic copolymer A containing a structural unit and having an acid value of more than 0 mgKOH / g and 85 mgKOH / g or less [hereinafter, also referred to as “specific (meth) acrylic copolymer A”. ], And a structural unit derived from the (meth) acrylic acid alkyl ester monomer and a structural unit derived from the monomer having a hydroxyl group, and the hydroxyl value is more than 0 mgKOH / g and 50 mgKOH / g or less. , The weight average molecular weight is smaller than the weight average molecular weight of the (meth) acrylic copolymer A (meth) acrylic copolymer B [hereinafter, also referred to as “specific (meth) acrylic copolymer B”. ], And the content ratio of the (meth) acrylic copolymer A to the (meth) acrylic copolymer B is 50/50 to 95/5 on a mass basis.
By having the above-mentioned structure, the binder composition of the present invention has excellent dispersibility of the ceramic powder when used for producing a slurry containing the ceramic powder and the solvent, and the excellent dispersibility of the ceramic powder is maintained over time. It is possible to prepare a slurry that can be held by.
In the present specification, "the excellent dispersibility can be maintained over time" is also referred to as "the excellent dispersion stability".

In the present specification, the specific (meth) acrylic copolymer A and the specific (meth) acrylic copolymer B are collectively referred to as "specific (meth) acrylic copolymer".

[Specific (meth) acrylic copolymer A]
The binder composition of the present invention contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a carboxy group, and has an acid value of more than 0 mgKOH / g. It contains a (meth) acrylic copolymer A of 85 mgKOH / g or less [that is, a specific (meth) acrylic copolymer A].

<Constituent unit derived from (meth) acrylic acid alkyl ester monomer>
The specific (meth) acrylic copolymer A contains a structural unit derived from the (meth) acrylic acid alkyl ester monomer.
The structural unit derived from the (meth) acrylic acid alkyl ester monomer contributes to the dispersion stability of the ceramic powder.

In the present specification, the “constituent unit derived from the (meth) acrylic acid alkyl ester monomer” means a structural unit formed by addition polymerization of the (meth) acrylic acid alkyl ester monomer.

The type of (meth) acrylic acid alkyl ester monomer is not particularly limited.
As the (meth) acrylic acid alkyl ester monomer, an unsubstituted (meth) acrylic acid alkyl ester monomer is preferable.
The alkyl group of the (meth) acrylic acid alkyl ester monomer may be linear, branched or cyclic.
The number of carbon atoms of the alkyl group is preferably 1 to 18, more preferably 1 to 8, and even more preferably 1 to 4.

Specific examples of the (meth) acrylic acid alkyl ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, and s-butyl (meth). Acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, i-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, i-nonyl (meth) acrylate, Examples thereof include n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate, and lauryl (meth) acrylate.
Among these, as the (meth) acrylic acid alkyl ester monomer, for example, methyl acrylate (MA), methyl methacrylate (MMA), ethyl acrylate (EA) from the viewpoint of having an appropriate interaction with ceramic powder. , And at least one selected from the group consisting of ethyl methacrylate (EMA) is preferred.

The specific (meth) acrylic copolymer A may contain only one type of structural unit derived from the (meth) acrylic acid alkyl ester monomer, or may contain two or more types.

The content (ratio) of the structural units derived from the (meth) acrylic acid alkyl ester monomer in the specific (meth) acrylic copolymer A is the content (ratio) of the structural units with respect to all the structural units of the specific (meth) acrylic copolymer A. It is preferably 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more.
Here, the content (ratio) of the structural unit derived from the (meth) acrylic acid alkyl ester monomer is 50% by mass or more with respect to all the structural units of the specific (meth) acrylic copolymer A. Means that the structural unit derived from the (meth) acrylic acid alkyl ester monomer is contained as the main component of the structural unit constituting the specific (meth) acrylic copolymer A.
The upper limit of the content (ratio) of the structural unit derived from the (meth) acrylic acid alkyl ester monomer in the specific (meth) acrylic copolymer A is not particularly limited, but for example, the specific (meth) acrylic copolymer is not particularly limited. It is preferably 97.0% by mass or less based on all the constituent units of the polymer A.

<Constituent unit derived from a monomer having a carboxy group>
The specific (meth) acrylic copolymer A contains a structural unit derived from a monomer having a carboxy group.
The structural unit derived from the monomer having a carboxy group in the specific (meth) acrylic copolymer A contributes to the improvement of the dispersion stability of the ceramic powder.
When the specific (meth) acrylic copolymer A contains a structural unit derived from a monomer having a carboxy group, reaggregation of the ceramic powder is suppressed due to steric hindrance due to the interaction of the carboxy group, and the ceramic powder is dispersed. Stability can be improved.

As used herein, the "constituent unit derived from a monomer having a carboxy group" means a structural unit formed by addition polymerization of a monomer having a carboxy group.

The type of monomer having a carboxy group is not particularly limited.
Specific examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, fumaric acid, itaconic acid, glutaconic acid, citraconic acid, and ω-carboxy-polycaprolactone mono (meth) acrylate [ For example, ω-carboxy-polycaprolactone (n≈2) monoacrylate], succinic acid ester (for example, 2-acryloyloxyethyl-succinic acid) and the like can be mentioned.
Among these, acrylic acid is preferable as the monomer having a carboxy group, for example, from the viewpoint of copolymerizability.

The specific (meth) acrylic copolymer A may contain only one type of structural unit derived from a monomer having a carboxy group, or may contain two or more types.

The content (ratio) of the structural units derived from the monomer having a carboxy group in the specific (meth) acrylic copolymer A is 0 with respect to all the structural units of the specific (meth) acrylic copolymer A. It is preferably more than mass% and 11% by mass or less, more preferably 0.02% by mass or more and 7% by mass or less, and further preferably 0.05% by mass or more and 5% by mass or less.
The content of the structural unit derived from the monomer having a carboxy group in the specific (meth) acrylic copolymer A exceeds 0% by mass with respect to all the structural units of the specific (meth) acrylic copolymer A. Since the steric hindrance due to the interaction of the carboxy groups favorably suppresses the reaggregation of the ceramic powder, the dispersion stability of the ceramic powder can be improved.
The content of the structural unit derived from the monomer having a carboxy group in the specific (meth) acrylic copolymer A is 11% by mass or less with respect to all the structural units of the specific (meth) acrylic copolymer A. If there is, the aggregation of the specific (meth) acrylic copolymers A is less likely to occur, so that the dispersion stability of the ceramic powder can be further improved.

<Other building blocks>
The specific (meth) acrylic copolymer A is the above-mentioned structural unit, that is, the structural unit derived from the (meth) acrylic acid alkyl ester monomer and the carboxy group within the range in which the effect of the present invention is exhibited. A structural unit other than the structural unit having the above (so-called other structural unit) may be included.

The monomer constituting the other structural unit is not particularly limited as long as it can be copolymerized with the monomer constituting the above-mentioned structural unit.
Specific examples of the monomers constituting other structural units include cyclic groups typified by cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, and phenoxyethyl (meth) acrylate (. Acryloalkyl (meth) acrylates represented by meta) acrylates, methoxyethyl (meth) acrylates and ethoxyethyl (meth) acrylates, styrene, α-methylstyrene, t-butylstyrene, p-chlorostyrene, chloromethylstyrene, and Aromatic monovinyl represented by vinyl toluene, vinyl cyanide represented by acrylonitrile and methacrylonitrile, vinyl acrylate, vinyl acetate, vinyl propionate, vinyl ester represented by vinyl versaticate, and a single amount thereof. Examples include various derivatives of the body.
Further, specific examples of the monomers constituting other constituent units include a monomer having a hydroxyl group and a monomer having an amino group, but the specific (meth) acrylic copolymer A has a hydroxyl group. It is preferable that the structural unit derived from the monomer having an amino group and / or the structural unit derived from the monomer having an amino group is not contained.

<< Acid value of specific (meth) acrylic copolymer A >>
The acid value of the specific (meth) acrylic copolymer A is more than 0 mgKOH / g and 85 mgKOH / g or less, preferably 0.2 mgKOH / g or more and 55 mgKOH / g or less, and 0.4 mgKOH / g or more. More preferably, it is 28 mgKOH / g or less.
The fact that the acid value of the specific (meth) acrylic copolymer A exceeds 0 mgKOH / g means that the specific (meth) acrylic copolymer A contains a structural unit derived from a monomer having a carboxy group. means.
When the acid value of the specific (meth) acrylic copolymer A is 85 mgKOH / g or less, aggregation of the specific (meth) acrylic copolymer A is unlikely to occur, so that the dispersibility and dispersion stability of the ceramic powder Can be improved.

The acid value of the specific (meth) acrylic copolymer A is calculated by the following formula. In the following calculation formula, 56.1 is the molecular weight of KOH.
Acid value (mgKOH / g)
= {(A1 / 100) ÷ A2} × 56.1 × 1000 × A3
A1: Percentage of monomer having a carboxy group in all the monomers used in the production of the specific (meth) acrylic copolymer A (unit: mass%)
A2: Molecular weight of the carboxy group-containing monomer used in the production of the specific (meth) acrylic copolymer A A3: Number of carboxy groups contained in one carboxy group-containing monomer molecule

When there are two or more types of monomers having a carboxy group used in the production of the specific (meth) acrylic copolymer A, the acid value of each monomer is determined according to the above formula. After that, the obtained values are summed to obtain the acid value.

<< Weight average molecular weight of specific (meth) acrylic copolymer A >>
The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is not particularly limited as long as it is larger than the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B.
The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is, for example, preferably 200,000 or more and 1.5 million or less, more preferably 250,000 or more and 1.5 million or less, and 250,000 or more and 80. It is more preferably 10,000 or less, and particularly preferably 300,000 or more and 400,000 or less.
When the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is 200,000 or more, the reaggregation of the ceramic powder is better suppressed by appropriate steric hindrance, so that the dispersion of the ceramic powder is stable. The sex can be improved.
When the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is 1.5 million or less, it can be mixed more appropriately when producing a slurry, and workability can be further improved.

The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is a value measured by the following method. Specifically, the measurement is performed according to the following (1) to (3).
(1) A solution of the specific (meth) acrylic copolymer A is applied to a release paper and dried at 100 ° C. for 1 minute to obtain a film-like specific (meth) acrylic copolymer A.
(2) A sample solution having a solid content concentration of 0.2% by mass is obtained by using the film-shaped specific (meth) acrylic copolymer A and tetrahydrofuran obtained in (1) above.
(3) Using gel permeation chromatography (GPC), the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A is measured as a standard polystyrene-equivalent value under the following conditions.

~conditions~
Measuring device: High-speed GPC (Model number: HLC-8220 GPC, manufactured by Tosoh Corporation)
Detector: Differential refractometer (RI) (built into HLC-8220, manufactured by Tosoh Corporation)
Column: 4 TSK-GEL GMHXL (manufactured by Tosoh Corporation) connected in series Column temperature: 40 ° C
Eluent: tetrahydrofuran Sample concentration: 0.2% by mass
Injection volume: 100 μL
Flow rate: 0.6 mL / min

<< Glass transition temperature of specific (meth) acrylic copolymer A >>
The glass transition temperature (Tg) of the specific (meth) acrylic copolymer A is not particularly limited, but is preferably 0 ° C. or higher and 50 ° C. or lower, and more preferably 0 ° C. or higher and 40 ° C. or lower. It is more preferably ° C. or higher and 35 ° C. or lower, and particularly preferably 10 ° C. or higher and 25 ° C. or lower.
When the glass transition temperature (Tg) of the specific (meth) acrylic copolymer A is within the above range, the produced green sheet has both strength and flexibility. For example, green even when an external force is applied during transportation. It tends to be hard to break, such as the sheet tearing.

The glass transition temperature (Tg) of the specific (meth) acrylic copolymer A is a value obtained by converting the absolute temperature (K) calculated from the following formula 1 into the Celsius temperature (° C.).
1 / Tg = m1 / Tg1 + m2 / Tg2 + ... + m (k-1) / Tg (k-1) + mk / Tgk (Equation 1)

In formula 1, Tg1, Tg2, ..., Tg (k-1), and Tgk are the absolute temperatures when each monomer constituting the specific (meth) acrylic copolymer A is used as a homopolymer. Each represents the glass transition temperature (Tg) represented by (K). m1, m2, ..., M (k-1), and mk represent the mole fractions of each monomer constituting the specific (meth) acrylic copolymer A, and m1 + m2 + ... + m ( k-1) + mk = 1.
The absolute temperature (K) can be converted to the Celsius temperature (° C) by subtracting 273 from the absolute temperature (K), and the Celsius temperature (° C) can be converted to the absolute temperature (K) by adding 273 to the Celsius temperature (° C). Can be converted to.

The "glass transition temperature (Tg) represented by the absolute temperature (K) when made into a homopolymer" is the absolute temperature (K) of the homopolymer produced by polymerizing the monomer alone. It refers to the glass transition temperature (Tg) represented by.
The glass transition temperature (Tg) of the homopolymer was measured using a differential scanning calorimetry device (DSC) (model number: EXSTAR6000, manufactured by Seiko Instruments Co., Ltd.) in a nitrogen stream, a measurement sample of 10 mg, and a temperature rise rate of 10 ° C./ It was measured under the condition of minutes, and the turning point of the obtained DSC curve was taken as the glass transition temperature (Tg) of the homopolymer.

The "glass transition temperature (Tg) represented by the Celsius temperature (° C.) when made into a homopolymer" of a typical monomer is as shown below.
2-Ethylhexyl acrylate (2EHA) is -76 ° C, 2-ethylhexyl methacrylate (2EHMA) is -10 ° C, n-butyl acrylate (n-BA) is -57 ° C, n-butyl methacrylate (n-BMA) is 21 ° C. , T-butyl acrylate (t-BA) at 41 ° C, t-butyl methacrylate (t-BMA) at 107 ° C, i-butyl methacrylate (i-BMA) at 48 ° C, methyl acrylate (MA) at 5 ° C, methyl. Methacrylate (MMA) at 103 ° C, isobonyl methacrylate (IBXMA) at 155 ° C, isobonyl acrylate (IBXA) at 96 ° C, cyclohexyl methacrylate (CHMA) at 56 ° C, ethyl acrylate (EA) at -27 ° C, ethyl methacrylate ( EMA) at 42 ° C, methacrylic acid at 185 ° C, 4-hydroxybutyl acrylate (4HBA) at −39 ° C, 2-hydroxyethyl acrylate (2HEA) at -15 ° C, 2-hydroxyethyl methacrylate (2HEMA) at 55 ° C, Acrylic acid (AA) at 163 ° C, isooctyl acrylate (i-OA) at −75 ° C, dimethylaminoethyl methacrylate (DM) at 18 ° C, ω-carboxy-polycaprolactone (n≈2) monoacrylate at −30 ° C. , And 2-acryloyloxyethyl-succinic acid is −40 ° C.

<< Content of specific (meth) acrylic copolymer A >>
The content of the specific (meth) acrylic copolymer A in the binder composition of the present invention is not particularly limited, but for example, from the viewpoint of improving the dispersibility and dispersion stability of the ceramic powder, the binder composition It is preferably 50% by mass or more and 95% by mass or less, more preferably 60% by mass or more and 90% by mass or less, and 75% by mass or more and 85% by mass or less with respect to the total solid content in the medium. More preferred.

In the present specification, the "total solid content in the binder composition" means the total mass of the binder composition when the binder composition does not contain a volatile component such as a solvent, and the binder composition is a solvent. When a volatile component such as a solvent is contained, it means the mass of the residue obtained by removing the volatile component such as a solvent from the binder composition.

[Specific (meth) acrylic copolymer B]
The binder composition of the present invention contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a hydroxyl group, and the hydroxyl value exceeds 0 mgKOH / g to 50 mgKOH / g. The (meth) acrylic copolymer B [that is, the specific (meth) acrylic copolymer B, which is less than the weight average molecular weight of the specific (meth) acrylic copolymer A and has the following weight average molecular weight. 〕including.

<Constituent unit derived from (meth) acrylic acid alkyl ester monomer>
The specific (meth) acrylic copolymer B contains a structural unit derived from the (meth) acrylic acid alkyl ester monomer.
The structural unit derived from the (meth) acrylic acid alkyl ester monomer contributes to the dispersibility of the ceramic powder.

The type of (meth) acrylic acid alkyl ester monomer is not particularly limited.
As the (meth) acrylic acid alkyl ester monomer, an unsubstituted (meth) acrylic acid alkyl ester monomer is preferable.
The alkyl group of the (meth) acrylic acid alkyl ester monomer may be linear, branched or cyclic.
The number of carbon atoms of the alkyl group is preferably 1 to 18, more preferably 1 to 8, and even more preferably 1 to 4.

Specific examples of the (meth) acrylic acid alkyl ester monomer are as described above, and thus description thereof will be omitted here.
Examples of the (meth) acrylic acid alkyl ester monomer include methyl acrylate (MA), methyl methacrylate (MMA), ethyl acrylate (EA), and ethyl methacrylate from the viewpoint of having an appropriate interaction with ceramic powder. At least one selected from the group consisting of (EMA) is preferable.

The specific (meth) acrylic copolymer B may contain only one type of structural unit derived from the (meth) acrylic acid alkyl ester monomer, or may contain two or more types.

The content (ratio) of the structural unit derived from the (meth) acrylic acid alkyl ester monomer in the specific (meth) acrylic copolymer B is based on all the structural units of the specific (meth) acrylic copolymer B. It is preferably 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more.
Here, the content (ratio) of the structural unit derived from the (meth) acrylic acid alkyl ester monomer is 50% by mass or more with respect to all the structural units of the specific (meth) acrylic copolymer B. Means that the structural unit derived from the (meth) acrylic acid alkyl ester monomer is contained as the main component of the structural unit constituting the specific (meth) acrylic copolymer B.
The upper limit of the content (ratio) of the structural unit derived from the (meth) acrylic acid alkyl ester monomer in the specific (meth) acrylic copolymer B is not particularly limited, but for example, the specific (meth) acrylic copolymer is not particularly limited. It is preferably 99.0% by mass or less based on all the constituent units of the polymer B.

<Constituent unit derived from a monomer having a hydroxyl group>
The specific (meth) acrylic copolymer (B) contains a structural unit derived from a monomer having a hydroxyl group.
The structural unit derived from the monomer having a hydroxyl group in the specific (meth) acrylic copolymer B contributes to the improvement of the dispersibility of the ceramic powder.
When the specific (meth) acrylic copolymer B contains a structural unit derived from a monomer having a hydroxyl group, the specific (meth) acrylic copolymer B is well wetted with the ceramic powder, so that the ceramic powder Dispersibility can be improved.

In the present specification, the “constituent unit derived from a monomer having a hydroxyl group” means a structural unit formed by addition polymerization of a monomer having a hydroxyl group.

The type of the monomer having a hydroxyl group is not particularly limited.
Specific examples of the monomer having a hydroxyl group include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-. Hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, 3-methyl-3-hydroxybutyl (meth) acrylate, 1,1 -Dimethyl-3-hydroxybutyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl-3-3 Examples thereof include hydroxyhexyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as N-hydroxyethyl (meth) acrylamide, 1,4-cyclohexanedimethanol monoacrylate, and dicaprolactone 2-acryloyloxy-ethyl ether.
Among these, as the monomer having a hydroxyl group, hydroxyalkyl (meth) acrylate is preferable from the viewpoint of good copolymerizability with the (meth) acrylic acid alkyl ester monomer.
As the hydroxyalkyl (meth) acrylate, for example, at least selected from the group consisting of 2-hydroxyethyl acrylate (2HEA) and 4-hydroxybutyl acrylate (4HBA) from the viewpoint of better dispersibility of the ceramic powder. One type is preferable.

The specific (meth) acrylic copolymer (B) may contain only one type of structural unit derived from a monomer having a hydroxyl group, or may contain two or more types.

The content (ratio) of the structural unit derived from the monomer having a hydroxyl group in the specific (meth) acrylic copolymer B is 0 mass with respect to all the structural units of the specific (meth) acrylic copolymer B. It is preferably more than% and 11% by mass or less, more preferably 1% by mass or more and 7% by mass or less, and further preferably 1.5% by mass or more and 6% by mass or less.
When the content of the structural unit derived from the monomer having a hydroxyl group in the specific (meth) acrylic copolymer B exceeds 0% by mass with respect to all the structural units of the specific (meth) acrylic copolymer B. Since the specific (meth) acrylic copolymer B is well wetted with the ceramic powder, the dispersibility of the ceramic powder can be improved.
The content of the structural unit derived from the monomer having a hydroxyl group in the specific (meth) acrylic copolymer B is 11% by mass or less with respect to all the structural units of the specific (meth) acrylic copolymer B. As a result, agglomeration of the specific (meth) acrylic copolymers B is less likely to occur, so that the dispersibility of the ceramic powder can be further improved.

<Other building blocks>
The specific (meth) acrylic copolymer B contains the above-mentioned structural units, that is, the structural units and hydroxyl groups derived from the (meth) acrylic acid alkyl ester monomer, within the range in which the effects of the present invention are exhibited. It may include a structural unit other than the constituent unit (so-called other structural unit).

The monomer constituting the other structural unit is not particularly limited as long as it can be copolymerized with the monomer constituting the above-mentioned structural unit.
Specific examples of the monomers constituting other structural units include cyclic groups typified by cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, and phenoxyethyl (meth) acrylate (. Acryloalkyl (meth) acrylates represented by meta) acrylates, methoxyethyl (meth) acrylates and ethoxyethyl (meth) acrylates, styrene, α-methylstyrene, t-butylstyrene, p-chlorostyrene, chloromethylstyrene, and Aromatic monovinyl represented by vinyl toluene, vinyl cyanide represented by acrylonitrile and methacrylonitrile, vinyl acrylate, vinyl acetate, vinyl propionate, vinyl ester represented by vinyl versaticate, and a single amount thereof. Examples include various derivatives of the body.
Further, specific examples of the monomers constituting other structural units include a monomer having a carboxy group and a monomer having an amino group, but the specific (meth) acrylic copolymer B is a specific (meth) acrylic copolymer. It is preferable that the structural unit derived from the monomer having a carboxy group and / or the structural unit derived from the monomer having an amino group is not contained.

<< Hydroxyl value of specific (meth) acrylic copolymer B >>
The hydroxyl value of the specific (meth) acrylic copolymer B is more than 0 mgKOH / g and 50 mgKOH / g or less, preferably 4 mgKOH / g or more and 34 mgKOH / g or less, and 7 mgKOH / g or more and 26 mgKOH / g or less. Is more preferable.
When the hydroxyl value of the specific (meth) acrylic copolymer B exceeds 0 mgKOH / g, it means that the specific (meth) acrylic copolymer B has a structural unit derived from a monomer having a hydroxyl group. ..
When the hydroxyl value of the specific (meth) acrylic copolymer B is 50 mgKOH / g or less, aggregation of the specific (meth) acrylic copolymer B is less likely to occur, so that the dispersibility of the ceramic powder can be improved. ..

The hydroxyl value of the specific (meth) acrylic copolymer B is calculated by the following formula. In the following calculation formula, 56.1 is the molecular weight of KOH.
Hydroxy group value (mgKOH / g)
= {(B1 / 100) ÷ B2} x 56.1 x 1000 x B3
B1: Ratio (unit: mass%) of the monomer having a hydroxyl group to all the monomers used in the production of the specific (meth) acrylic copolymer B.
B2: Molecular weight of the hydroxyl group-containing monomer used in the production of the specific (meth) acrylic copolymer B B3: Number of hydroxyl groups contained in one hydroxyl group-containing monomer molecule

When there are two or more types of monomers having hydroxyl groups used in the production of the specific (meth) acrylic copolymer B, the hydroxyl values of each monomer were determined according to the above formula. After that, the obtained values are summed to obtain the hydroxyl value.

<< Weight average molecular weight of specific (meth) acrylic copolymer B >>
The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B is not particularly limited as long as it is smaller than the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A.
The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B is, for example, preferably 10,000 or more and less than 250,000, and more preferably 30,000 or more and 200,000 or less. It is more preferably 5,000 or more and 180,000 or less.
When the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B is 10,000 or more, the dispersibility of the ceramic powder can be further improved.
When the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B is less than 250,000, the coatability of the slurry can be further improved.

The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer B is measured by the same method as the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A described above. The explanation will be omitted.

<< Glass transition temperature of specific (meth) acrylic copolymer B >>
The glass transition temperature (Tg) of the specific (meth) acrylic copolymer B is not particularly limited, but is preferably −20 ° C. or higher and 25 ° C. or lower, and more preferably −20 ° C. or higher and 15 ° C. or lower. , -15 ° C or higher and 10 ° C or lower, and particularly preferably -5 ° C or higher and 10 ° C or lower.
When the glass transition temperature (Tg) of the specific (meth) acrylic copolymer B is within the above range, the action of the specific (meth) acrylic copolymer B on the ceramic powder becomes stronger, so that the ceramic powder Dispersibility can be further improved.

The glass transition temperature (Tg) of the specific (meth) acrylic copolymer B is calculated by the same method as the glass transition temperature (Tg) of the specific (meth) acrylic copolymer A described above. The explanation will be omitted.

<< Content of specific (meth) acrylic copolymer B >>
The content of the specific (meth) acrylic copolymer B in the binder composition of the present invention is not particularly limited, but for example, from the viewpoint of improving the dispersibility and dispersion stability of the ceramic powder, the binder composition It is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, and 15% by mass or more and 25% by mass or less with respect to the total solid content in the medium. More preferred.

(Content ratio of specific (meth) acrylic copolymer A to specific (meth) acrylic copolymer B)
In the binder composition of the present invention, the content ratio of the specific (meth) acrylic copolymer A to the specific (meth) acrylic copolymer B (hereinafter, also referred to as “content ratio A / B”) is based on mass. It is 50/50 to 95/5, preferably 60/40 to 95/5, more preferably 70/30 to 95/5, and preferably 70/30 to 90/10. More preferred.
When the content ratio A / B is 50/50 or more on a mass basis, the reaggregation of the ceramic powder is satisfactorily suppressed by appropriate steric hindrance, so that the dispersion stability of the ceramic powder can be improved.
When the content ratio A / B is 95/5 or less on a mass basis, the dispersibility of the ceramic powder can be improved.

[Method for producing specific (meth) acrylic copolymer]
The method for producing the specific (meth) acrylic copolymer A and the specific (meth) acrylic copolymer B [that is, the specific (meth) acrylic copolymer] is not particularly limited.
The specific (meth) acrylic copolymer is produced by polymerizing the above-mentioned monomers by a known polymerization method typified by, for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method. it can.

The glass transition temperature (Tg) of the specific (meth) acrylic copolymer can be appropriately adjusted by using, for example, two or more types of monomers having different glass transition temperatures (Tg) when they are homopolymers.
The weight average molecular weight (Mw) of the specific (meth) acrylic copolymer can be determined by adjusting the polymerization temperature, polymerization time, amount of organic solvent used, type of polymerization initiator, amount of polymerization initiator used, and the like. , Can be set to the desired value.

As a polymerization method, solution polymerization is preferable because the treatment step is relatively simple and the binder composition of the present invention can be prepared in a short time after production.
In solution polymerization, a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent used as needed are generally charged in a polymerization tank, and in a nitrogen stream and / or at the reflux temperature of the organic solvent. Heat and react for several hours with stirring. In this case, at least a part of the organic solvent, the monomer, the polymerization initiator and / or the chain transfer agent may be added sequentially.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbon compounds, aliphatic or alicyclic hydrocarbon compounds, ester compounds, ketone compounds, glycol ether compounds, alcohol compounds and the like.
More specifically, examples of the organic solvent used in the polymerization reaction include benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetraline and decalin. And aromatic hydrocarbon compounds typified by aromatic naphtha, n-hexane, n-heptane, n-octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, and fat typified by terepine oil. Represented by group or alicyclic hydrocarbon compounds, ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, and methyl benzoate. Estel compounds, acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone, and ketone compounds typified by methylcyclohexanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Glycol ether compounds typified by ether and diethylene glycol monobutyl ether, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol, and t. -Alcohol compounds typified by butyl alcohol can be mentioned.
At the time of the polymerization reaction, only one of these organic solvents may be used, or two or more of these organic solvents may be mixed and used.

In the production of the specific (meth) acrylic copolymer, it is preferable to use an organic solvent that does not easily cause chain transfer during the polymerization reaction of the aromatic hydrocarbon compound, the ester compound, the ketone compound, the alcohol compound, etc. Meta) From the viewpoint of solubility of the acrylic copolymer and ease of polymerization reaction, it is preferable to use toluene, ethyl acetate or the like.

Examples of the polymerization initiator include organic peroxides and azo compounds used in ordinary solution polymerization.
Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propylperoxydicarbonate, and di-2-ethylhexylperoxydi. Carbonate, t-butylperoxypivalate, 2,2-bis (4,5-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,5-di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,5-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,54-di-α-cumylperoxycyclohexyl) propane, 2,2-bis (4,4) Examples include -di-t-butylperoxycyclohexyl) butane and 2,2-bis (4,5-di-t-octylperoxycyclohexyl) butane.
Examples of the azo compound include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile) (ABVN), and 2,2'-azobis (4-). Methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), and 2,2'-azobis (isobutyric acid) dimethyl.
At the time of the polymerization reaction, only one kind of these polymerization initiators may be used, or two or more kinds thereof may be mixed and used.

The amount of the polymerization initiator used is not particularly limited, and is appropriately set according to the molecular weight of the target specific (meth) acrylic copolymer.

In the production of the specific (meth) acrylic copolymer, a chain transfer agent may be used as needed as long as the object and effect of the present invention are not impaired.
Examples of the chain transfer agent include cyanoacetic acid, an alkyl ester compound having 1 to 8 carbon atoms of cyanoacetic acid, bromoacetic acid, an alkyl ester compound having 1 to 8 carbon atoms of bromoacetic acid, α-methylstyrene, anthracene, phenanthrene, and fluorene. , And aromatic compounds such as 9-phenylfluorene, p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, and aromatic nitro compounds such as p-nitrotoluene, benzoquinone and A benzoquinone derivative typified by 2,3,5,6-tetramethyl-p-benzoquinone, a borane derivative typified by tributylborane, carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane. , Tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, halogenated hydrocarbon compounds typified by 3-chloro-1-propene, aldehyde compounds typified by chloral and furaldehyde, alkyl having 1 to 18 carbon atoms. For mercaptan compounds, aromatic mercaptan compounds typified by thiophenols and toluene mercaptans, mercaptoacetic acid, alkyl ester compounds having 1 to 10 carbon atoms of mercaptoacetic acid, hydroxyalkyl mercaptan compounds having 1 to 12 carbon atoms, and binen and turpinolene. A typical terpen compound can be mentioned.

When a chain transfer agent is used in the production of the specific (meth) acrylic copolymer, the amount of the chain transfer agent used is not particularly limited, and depends on the molecular weight of the target specific (meth) acrylic copolymer. , Set as appropriate.

The polymerization temperature is not particularly limited, and is appropriately set according to the molecular weight of the target specific (meth) acrylic copolymer.

[Other ingredients]
The binder composition of the present invention may contain components other than the above-mentioned components (so-called other components), if necessary, as long as the effects of the present invention are not impaired.
Examples of other components include polymers other than the specific (meth) acrylic copolymer A and the specific (meth) acrylic copolymer B, and plasticizers (dioctyl phthalate, dibutyl phthalate, polyester, etc.). Be done.

[Ceramic molding composition]
The composition for ceramic molding of the present invention includes the above-mentioned binder composition of the present invention, ceramic powder, and a solvent.
Since the composition for ceramic molding of the present invention contains the binder composition of the present invention, the dispersibility of the ceramic powder is excellent, and the excellent dispersibility can be maintained over time.

[Ceramic powder]
The ceramic molding composition of the present invention contains a ceramic powder.
The ceramic powder is not particularly limited, and examples thereof include powders of alumina, ferrite, aluminum nitride, silicon nitride and the like.

The ceramic molding composition of the present invention may contain only one type of ceramic powder, or may contain two or more types of ceramic powder.

The average particle size of the ceramic powder contained in the ceramic molding composition of the present invention is, for example, 0.5 μm to 10 μm.
Since the composition for ceramic molding of the present invention contains the binder composition of the present invention, both the dispersibility and the dispersion stability of the ceramic powder are excellent even when the average particle size of the ceramic powder is 10 μm or less.
In the present specification, the average particle size of the ceramic powder means a particle size in which the volume accumulation of the detection frequency is 50% in the volume-based particle size distribution measured by using the laser diffraction type particle size distribution measuring device.

The content of the ceramic powder in the ceramic molding composition of the present invention is not particularly limited, but is preferably 50% by mass to 95% by mass, preferably 60% by mass, based on the total mass of the ceramic molding composition, for example. It is more preferably% to 88% by mass, and further preferably 70% to 80% by mass.

〔solvent〕
The ceramic molding composition of the present invention contains a solvent.
The solvent is not particularly limited, and for example, toluene, ethyl acetate, butyl acetate, ethyl alcohol, methyl alcohol, n-butyl alcohol, n-propyl alcohol, i-propyl alcohol, acetone, methyl ethyl ketone, methyl-i-butyl ketone, etc. Examples thereof include xylene, hexane, cyclohexane, methylene chloride, trichloroethylene, perchloroethylene, chlorobenzene, water and the like.

The ceramic molding composition of the present invention may contain only one type of solvent, or may contain two or more types of solvent.

The content of the solvent in the ceramic molding composition of the present invention is not particularly limited, but is, for example, 5% by mass to 35% by mass with respect to the total mass of the ceramic molding composition from the viewpoint of coatability. It is more preferable, it is more preferably 10% by mass to 30% by mass, and further preferably 15% by mass to 25% by mass.

[Other ingredients]
The ceramic molding composition of the present invention may contain components other than the binder composition of the present invention, the ceramic powder, and the solvent (so-called other components), if necessary.
Other components in the composition for ceramic molding of the present invention include dispersants (polyethylene glycol, polycarboxylic acid-based dispersants, naphthalene sulfonic acid formarin condensation-based dispersants, polyether-based dispersants, polyalkylene polyamine-based dispersants, and the like. Alkyl sulfonic acid-based dispersant, quaternary ammonium-based dispersant, alkyl polyamine-based dispersant, polyphosphate-based dispersant, etc.), sintering aid [CaO, MgO, SiO ₂ , Fe ₂ O ₃ , Na ₂ O, TiO ₂ , MgCO ₃ , Mg ₃ Si ₄ O ₁₀ (OH) _2, etc. powder], leveling agent, defoaming agent, and the like can be mentioned.

[Manufacturing method of ceramic molding composition]
The method for producing the ceramic molding composition of the present invention is not particularly limited.
The ceramic molding composition of the present invention can be produced, for example, by mixing the binder composition of the present invention, ceramic powder, a solvent, and other components added as necessary.
The mixing method is not particularly limited, and examples thereof include a mixing method using a known mixer such as a ball mill, a blender mill, or a three-roll mill.

[Ceramic green sheet]
The ceramic green sheet of the present invention includes the binder composition of the present invention described above and the ceramic powder.
Since the ceramic green sheet of the present invention contains the binder composition of the present invention, it tends to be less likely to cause uneven thickness. The ceramic green sheet of the present invention can be suitably used for manufacturing a ceramic substrate.

The ceramic powder has the same meaning as the ceramic powder described in "Ceramic molding composition", and the preferred examples are also the same. Therefore, the description thereof is omitted here.

The ceramic green sheet of the present invention may contain only one type of ceramic powder, or may contain two or more types of ceramic powder.

The content of the ceramic powder in the ceramic green sheet of the present invention is not particularly limited and can be appropriately set according to the intended purpose.
The content of the ceramic powder in the ceramic green sheet of the present invention is generally 70% by mass to 99% by mass and 80% by mass to 97% by mass with respect to the total mass of the ceramic green sheet. preferable.

The ceramic green sheet of the present invention may contain components (so-called other components) other than the binder composition and the ceramic powder of the present invention, if necessary.
Examples of other components in the ceramic green sheet of the present invention include plasticizers, dispersants, leveling agents, antifoaming agents and the like.

The thickness of the ceramic green sheet of the present invention is not particularly limited, and can be appropriately set according to the intended purpose.
The thickness of the ceramic green sheet of the present invention is generally 50 μm to 1000 μm, preferably 100 μm to 500 μm.

The method for producing the ceramic green sheet of the present invention is not particularly limited.
The ceramic green sheet of the present invention is, for example, a slurry-like composition containing, for example, the binder composition of the present invention, a ceramic powder, a solvent, and other components added as needed (that is, the present invention. It can be produced by applying a ceramic molding composition) onto a support and drying the formed coating film.

The support is not particularly limited, and examples thereof include a base material containing a polyester such as polyethylene terephthalate and polyethylene naphthalate, and a resin such as polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, and polyvinyl chloride.
It is preferable that the support has a surface treatment on the side on which the ceramic green sheet of the present invention is formed, in order to impart releasability.
The surface treatment is not particularly limited, and examples thereof include a surface treatment using a release agent such as a silicone-based release agent, a fluorine-based release agent, and a wax-based release agent.

The coating method is not particularly limited, and examples thereof include known coating methods using various roll coaters typified by an applicator and a comma coater (registered trademark).
The drying method is not particularly limited, and examples thereof include a known drying method using a hot air dryer.
The drying conditions are not particularly limited and can be appropriately set according to the content of the solvent in the coating film, the thickness of the coating film, and the like.

In addition to the methods described above, the ceramic green sheet of the present invention uses a powdery composition containing the binder composition of the present invention, ceramic powder, and other components added as necessary in a molding machine. It can also be manufactured by filling and pressure molding.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples as long as the gist is not exceeded.

[Production of (meth) acrylic copolymer A]
[Manufacturing Example A-1]
788.2 parts by mass of ethyl acetate (organic solvent) was charged into a reactor equipped with a stirrer, a reflux condenser, a sequential dropping device, and a thermometer.
Then, in another container, 56.2 parts by mass of methyl acrylate (MA; acrylic acid alkyl ester monomer), 88.5 parts by mass of ethyl methacrylate (EMA; methacrylic acid alkyl ester monomer), and acrylic acid (AA). After charging a monomer mixture consisting of 44.8 parts by mass of (monomer having a carboxy group) into a reactor, 2,2'-azobisisobutyronitrile (AIBN; polymerization initiator) is placed in the reactor. ) 0.45 parts by mass was added. After the addition of this polymerization initiator, reflux was carried out at the reflux temperature for 60 minutes.
Then, under reflux temperature conditions, from 796.0 parts by mass of methyl acrylate (MA; acrylic acid alkyl ester monomer) and 506.1 parts by mass of ethyl methacrylate (EMA; methacrylate alkyl ester monomer) in the reactor. A mixture consisting of 149.0 parts by mass of ethyl acetate and 0.45 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was sequentially added dropwise over 120 minutes. After completion of the dropping, the same temperature was further maintained for 90 minutes to obtain a polymerization reaction product (a1). A mixture consisting of 234.9 parts by mass of toluene (organic solvent) and 1.34 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added to the obtained polymerization reaction product (a1) over 60 minutes. It was dropped sequentially. After completion of the dropping, the same temperature was further maintained for 70 minutes to obtain a polymerization reaction product (a2). The obtained polymerization reaction product (a2) was diluted with ethyl acetate and toluene to a solid content concentration of 40% by mass, and then cooled to obtain a solution of the (meth) acrylic copolymer A-1.
The "solid content concentration" as used herein means that volatile components such as a solvent have been removed from the solution of the (meth) acrylic copolymer A-1 in the solution of the (meth) acrylic copolymer A-1. It means the mass ratio of the remaining components. The same applies to the following solutions of the (meth) acrylic copolymers A-2 to A-14.

[Production Examples A-2 and A-10 to A-12]
In Production Example A-1, the same operation as in Production Example A-1 was carried out except that the monomer composition of the (meth) acrylic copolymer A was changed to the monomer composition shown in Table 1. Solutions of (meth) acrylic copolymers A-2 and A-10 to A-12 having a component concentration of 40% by mass were obtained.

[Manufacturing Examples A-6 to A-8]
In Production Example A-1, the weight average molecular weight (Mw) of the (meth) acrylic copolymer A is shown in Table 1 by adjusting at least one of the amount of the organic solvent used and the amount of the polymerization initiator used. The same operations as in Production Example A-1 were carried out except that the weight average molecular weight (Mw) was changed, and the (meth) acrylic copolymers A-6 to A-8 having a solid content concentration of 40% by mass were used. Each solution was obtained.

[Production Examples A-3 to A-5, A-9, A-13, and A-14]
In Production Example A-1, the monomer composition of the (meth) acrylic copolymer A was changed to the monomer composition shown in Table 1, and the amount of the organic solvent used and the amount of the polymerization initiator used. By adjusting at least one of the above, the weight average molecular weight (Mw) of the (meth) acrylic copolymer A was changed to the weight average molecular weight (Mw) shown in Table 1, except that the weight average molecular weight (Mw) was changed to that of Production Example A-1. The same operation was carried out to obtain solutions of (meth) acrylic copolymers A-3 to A-5, A-9, A-13, and A-14 having a solid content concentration of 40% by mass.

(Meta) Acrylic copolymers A-1 to A-14 monomer composition (unit: mass%), acid value (unit: mgKOH / g) or hydroxyl value (unit: mgKOH / g), glass transition temperature (Tg, unit: ° C.), and the weight-average molecular weight [Mw, ten thousand (in the table, "× 10 ⁴ hereinafter)] shown in Table 1.
The glass transition temperature (Tg) of the (meth) acrylic copolymers A-1 to A-14 is the same as the method at the glass transition temperature (Tg) of the specific (meth) acrylic copolymer A described above. Calculated by
The weight average molecular weight (Mw) of the (meth) acrylic copolymers A-1 to A-14 is the same as the method for the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A described above. Measured by

The acid values of the (meth) acrylic copolymers A-1 to A-10, A-12, and A-14 are the same as the method for calculating the acid value of the specific (meth) acrylic copolymer A described above. It was obtained by the calculation method of. For example, the acid value of the (meth) acrylic copolymer A-1 was determined as follows. The obtained value was rounded to the second decimal place. The content of AA (A1) in the (meth) acrylic copolymer A-1 is 3.0% by mass, and the molecular weight of AA (A2) is 72.06. The number of carboxy groups (A3) contained in one molecule of AA is 1.
Acid value of (meth) acrylic copolymer A-1 (mgKOH / g) = {(A1 / 100) ÷ A2} × 56.1 × 1000 × A3 = {(3.0/100) ÷ 72.06 } × 56.1 × 1000 × 1 = 23.35 ・ ・ ・ ≒ 23.4

The hydroxyl values of the (meth) acrylic copolymers A-13 and A-14 were obtained by the same calculation method as the above-mentioned calculation method of the hydroxyl values of the specific (meth) acrylic copolymer B. For example, the hydroxyl value of the (meth) acrylic copolymer A-13 was determined as follows. The obtained value was rounded to the second decimal place. The content of 2HEA (B1) in the (meth) acrylic copolymer A-13 is 3.0% by mass, and the molecular weight of 2HEA (B2) is 116.12. The number of hydroxyl groups (B3) contained in one molecule of 2HEA is 1.
Hydroxy group value (mgKOH / g) of (meth) acrylic copolymer A-13 = {(B1 / 100) ÷ B2} × 56.1 × 1000 × B3 = {(3.0/100) ÷ 116.12 } × 56.1 × 1000 × 1 = 14.49 ・ ・ ・ ≒ 14.5

Details of each monomer shown in Table 1 are as shown below.
"MA": Methyl acrylate (acrylic acid alkyl ester monomer)
"EA": Ethyl acrylate (acrylic acid alkyl ester monomer)
"EMA": ethyl methacrylate (methacrylic acid alkyl ester monomer)
"MMA": Methyl methacrylate (methacrylic acid alkyl ester monomer)
"AA": Acrylic acid (monomer having a carboxy group)
"HOA-MS" [trade name, manufactured by Kyoeisha Chemical Co., Ltd.]: 2-acryloyloxyethyl-succinic acid (monomer having a carboxy group)
"2HEA": 2-hydroxyethyl acrylate (monomer having a hydroxyl group)

In Table 1, "-" means that the monomer in the corresponding column is not used.
In Table 1, "glass transition temperature (Tg)" is simply referred to as "Tg", and "weight average molecular weight (Mw)" is simply referred to as "Mw".

[Manufacture of (meth) acrylic copolymer B]
[Production Example B-1]
1540.0 parts by mass of ethyl acetate (organic solvent) was charged into a reactor equipped with a stirrer, a reflux condenser, a sequential dropping device, and a thermometer.
Then, in another container, 1209.0 parts by mass of methyl acrylate (MA; acrylic acid alkyl ester monomer), 263.5 parts by mass of ethyl methacrylate (EMA; methacrylic acid alkyl ester monomer), and 2-hydroxyethyl. 1550.0 parts by mass of a monomer mixture consisting of 77.5 parts by mass of acrylate (2HEA; monomer having a hydroxyl group) was prepared.
Next, 157.7 parts by mass (amount corresponding to 10.2% by mass of the monomer mixture) of the prepared monomer mixture was charged into the reactor, and then 2,2'-in the reactor. 0.46 parts by mass of azobisisobutyronitrile (AIBN; polymerization initiator) was added. After the addition of this polymerization initiator, reflux was carried out at the reflux temperature for 60 minutes.
Then, under reflux temperature conditions, the remaining 1392.3 parts by mass of the monomer mixture (amount corresponding to 89.8% by mass of the monomer mixture), 292.1 parts by mass of ethyl acetate, and A mixture consisting of 2.81 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was sequentially added dropwise over 120 minutes. After completion of the dropping, the same temperature was further maintained for 90 minutes to obtain a polymerization reaction product (a1). A mixture consisting of 243.0 parts by mass of toluene (organic solvent) and 1.40 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added to the obtained polymerization reaction product (a1) over 60 minutes. It was dropped sequentially. After completion of the dropping, the same temperature was further maintained for 70 minutes to obtain a polymerization reaction product (a2). The obtained polymerization reaction product (a2) was diluted with ethyl acetate and toluene to a solid content concentration of 40% by mass, and then cooled to obtain a solution of the (meth) acrylic copolymer B-1.
The "solid content concentration" as used herein means that volatile components such as a solvent have been removed from the solution of the (meth) acrylic copolymer B-1 in the solution of the (meth) acrylic copolymer B-1. It means the mass ratio of the remaining components. The same applies to each of the following (meth) acrylic copolymers B-2 to B-14 solutions.

[Production Examples B-2 to B-5, B-8 to B-11, and B-14]
In Production Example B-1, the same operation as in Production Example B-1 was performed except that the monomer composition of the (meth) acrylic copolymer B was changed to the monomer composition shown in Table 2, and the solid was formed. Solutions of (meth) acrylic copolymers B-2 to B-5, B-8 to B-11, and B-14 having a component concentration of 40% by mass were obtained.

[Production Examples B-6, B-7, B-12, and B-13]
Table 2 shows the weight average molecular weight (Mw) of the (meth) acrylic copolymer B by adjusting at least one of the amount of the organic solvent used and the amount of the polymerization initiator used in Production Example B-1. The same operation as in Production Example B-1 was carried out except that the weight average molecular weight (Mw) was changed, and the (meth) acrylic copolymers B-6 and B-7 having a solid content concentration of 40% by mass were carried out. Each solution of B-12 and B-13 was obtained.

(Meta) Acrylic copolymer B-1 to B-14 monomer composition (unit: mass%), hydroxyl value (unit: mgKOH / g) or acid value (unit: mgKOH / g), glass transition temperature (Tg, unit: ° C.), and the weight-average molecular weight [Mw, ten thousand (in the table, "× 10 ⁴ hereinafter)] shown in Table 2.
The glass transition temperature (Tg) of the (meth) acrylic copolymers B-1 to B-14 is the same as the method at the glass transition temperature (Tg) of the specific (meth) acrylic copolymer A described above. Calculated by
The weight average molecular weight (Mw) of the (meth) acrylic copolymers B-1 to B-14 is the same as the method for the weight average molecular weight (Mw) of the specific (meth) acrylic copolymer A described above. Measured by
The hydroxyl values of the (meth) acrylic copolymers B-1 to B-14 were obtained by the same calculation method as the above-mentioned calculation method of the hydroxyl values of the specific (meth) acrylic copolymer B.
The acid value of the (meth) acrylic copolymers B-1 to B-14 was determined by the same calculation method as the above-mentioned calculation method of the acid value of the specific (meth) acrylic copolymer A.

Details of each monomer shown in Table 2 are as shown below.
"MA": Methyl acrylate (acrylic acid alkyl ester monomer)
"EA": Ethyl acrylate (acrylic acid alkyl ester monomer)
"EMA": ethyl methacrylate (methacrylic acid alkyl ester monomer)
"MMA": Methyl methacrylate (methacrylic acid alkyl ester monomer)
"2HEA": 2-hydroxyethyl acrylate (monomer having a hydroxyl group)
"4HBA": 4-Hydroxybutyl acrylate (monomer having a hydroxyl group)
"AA": Acrylic acid (monomer having a carboxy group)

In Table 2, "-" means that the monomer in the corresponding column is not used.
In Table 2, "glass transition temperature (Tg)" is simply referred to as "Tg", and "weight average molecular weight (Mw)" is simply referred to as "Mw".

[Preparation of composition for ceramic molding]
[Examples 1 to 21, Comparative Examples 1 to 8, Comparative Example 10, and Comparative Example 11]
-Preparation of binder composition for ceramic molding-
The solution of the (meth) acrylic copolymer A and the solution of the (meth) acrylic copolymer B produced above are mixed in the combination shown in Table 3 so as to have the content ratio shown in Table 3. , A solution of a binder composition for ceramic molding was prepared.

-Preparation of ceramic molding composition-
10 parts by mass of the solution (solid content concentration: 40% by mass) of the binder composition for ceramic molding prepared above, ceramic powder [trade name: AL-M41-01, main component: alumina, average particle size: 2.0 μm , Sumitomo Chemical Co., Ltd.] 100 parts by mass of toluene (solvent), and 153 g of alumina balls (φ3 mm) were put into an alumina pot [capacity: 500 mL], and after stirring and mixing, Using a planetary ball mill (model: P-5, manufactured by Fritsche), the mixture was stirred and mixed at 360 rpm (revolutions per minute) for 1 hour to prepare a slurry-like ceramic molding composition.

[Comparative Example 9]
The solution of the (meth) acrylic copolymer A-1 produced above was used as a solution of the binder composition for ceramic molding, and a slurry-like composition for ceramic molding was prepared by the same method as in Example 1. did.

[Comparative Example 12]
The solution of the (meth) acrylic copolymer A-14 produced above was used as a solution of the binder composition for ceramic molding, and a slurry-like composition for ceramic molding was prepared by the same method as in Example 1. did.

[Comparative Example 13]
-Preparation of binder composition for ceramic molding-
The solution of the (meth) acrylic copolymer A-1 produced above and polyethylene glycol were mixed so as to have the content ratio shown in Table 3 to prepare a solution of a binder composition for ceramic molding.

-Preparation of ceramic molding composition-
Using the solution of the binder composition for ceramic molding prepared above, a slurry-like composition for ceramic molding was prepared by the same method as in Example 1.

[Comparative Example 14]
-Preparation of polyvinyl butyral solution-
40 parts by mass of polyvinyl butyral was dissolved in 100 parts by mass of a mixed solution of ethyl acetate and toluene [ethyl acetate / toluene = 50/50 (volume ratio)] to prepare a polyvinyl butyral solution having a solid content concentration of 40% by mass. ..

The polyvinyl butyral solution prepared above was used as a solution of the binder composition for ceramic molding, and a slurry-like composition for ceramic molding was prepared by the same method as in Example 1.

[Evaluation]
1. 1. Initial dispersibility 30 mL of the ceramic molding composition prepared above was weighed into a transparent glass bottle having a capacity of 50 mL. Next, the transparent glass bottle containing the ceramic molding composition was allowed to stand in an environment with an ambient temperature of 23 ° C. and 50% RH.
Then, the state of the ceramic molding composition was visually observed over time, and the initial dispersibility of the ceramic powder was evaluated according to the following evaluation criteria. The results are shown in Table 3.
If the evaluation result is "A", "B" or "C", it is judged that the composition is a ceramic molding composition having excellent initial dispersibility of the ceramic powder.

-Evaluation criteria-
A: No sediment was confirmed even after 120 hours or more from standing.
B: Sedimentation was confirmed 48 hours or more and less than 120 hours after standing.
C: Sedimentation was confirmed 24 hours or more and less than 48 hours after standing.
D: Sedimentation was confirmed less than 24 hours after standing.

2. 2. Dispersion Stability 30 mL of the ceramic molding composition prepared above was weighed into a transparent glass bottle having a capacity of 50 mL. Next, the transparent glass bottle containing the ceramic molding composition was allowed to stand in an environment with an ambient temperature of 23 ° C. and 50% RH.
Then, the state of the ceramic molding composition was visually observed over time, and the dispersion stability of the ceramic powder was evaluated according to the following evaluation criteria. The results are shown in Table 3.
If the evaluation result is "A", "B" or "C", it is judged that the composition is a ceramic molding composition having excellent dispersion stability of the ceramic powder.

-Evaluation criteria-
A: No sediment was confirmed even after 3 weeks or more from standing.
B: Sedimentation was confirmed within 2 to 3 weeks after standing.
C: Sedimentation was confirmed within 1 week or more and less than 2 weeks after standing.
D: Sedimentation was confirmed less than 1 week after standing.

In Table 3, "-" means that the corresponding component is not contained.

As shown in Table 3, all of the ceramic molding compositions of Examples 1 to 21 prepared using the ceramic molding binder composition of the present invention gave good results in the evaluation of initial dispersibility and dispersion stability. showed that.
From the above results, the binder composition for ceramic molding of the present invention is excellent in dispersibility of the ceramic powder and has excellent dispersibility when used for producing a slurry containing the ceramic powder and the solvent (that is, the composition for ceramic molding). It has been clarified that a slurry capable of retaining its excellent dispersibility over time can be produced.

On the other hand, none of the ceramic molding compositions of Comparative Examples 1 to 14 produced without using the ceramic molding binder composition of the present invention showed good results in the evaluation of dispersion stability.

[Ceramic green sheet production]
Using each ceramic molding composition of Examples 1 to 21, a ceramic green sheet was prepared as follows.
The ceramic molding composition, which has been prepared for 3 weeks, is applied to the surface-treated surface of a polyester film (support, thickness: 100 μm) surface-treated with a silicone-based mold release agent, and the thickness after drying becomes 100 μm. As described above, the coating was applied using an applicator to form a coating film. Next, the formed coating film was left at room temperature for 1 hour and then dried in a hot air dryer set at 80 ° C. for another 1 hour to prepare a ceramic green sheet.

When the produced ceramic green sheet was visually observed, no uneven thickness was confirmed in any of the ceramic green sheets.

Claims (7)

It contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a carboxy group, and has an acid value of more than 0 mgKOH / g and 85 mgKOH / g or less (meth). ) Acrylic copolymer A and
It contains a structural unit derived from a (meth) acrylic acid alkyl ester monomer and a structural unit derived from a monomer having a hydroxyl group, and has a hydroxyl value of more than 0 mgKOH / g and 50 mgKOH / g or less, and has a weight average. The (meth) acrylic copolymer B having a molecular weight smaller than the weight average molecular weight of the (meth) acrylic copolymer A is included.
A binder composition for ceramic molding in which the content ratio of the (meth) acrylic copolymer A to the (meth) acrylic copolymer B is 50/50 to 95/5 on a mass basis. The binder composition for ceramic molding according to claim 1, wherein the (meth) acrylic copolymer A has a weight average molecular weight of 250,000 or more and 1.5 million or less. The binder composition for ceramic molding according to claim 1 or 2, wherein the weight average molecular weight of the (meth) acrylic copolymer B is 10,000 or more and less than 250,000. The binder composition for ceramic molding according to any one of claims 1 to 3, wherein the glass transition temperature of the (meth) acrylic copolymer A is 0 ° C. or higher and 40 ° C. or lower. The binder composition for ceramic molding according to any one of claims 1 to 4, wherein the glass transition temperature of the (meth) acrylic copolymer B is −20 ° C. or higher and 15 ° C. or lower. A ceramic molding composition containing the binder composition for ceramic molding according to any one of claims 1 to 5, a ceramic powder, and a solvent. A ceramic green sheet containing the binder composition for ceramic molding according to any one of claims 1 to 5 and a ceramic powder.