Binder composition for firing, and paste for firing

Abstract

To provide an acrylic polymer (A) that can be blended in a sintering binder composition to improve the strength of a green sheet prepared from a sintering paste comprising the sintering binder composition without impairing the pyrolytic properties of the sintering binder composition.SOLUTION: An acrylic polymer (A) is blended in a sintering binder composition, the acrylic polymer (A) comprising a constitutional unit (a) represented by formula (1). In the formula (1), R1 is a hydrogen atom or a methyl group, and R2 is methylene group, an ethylene group or an ethoxyethylene group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an acrylic polymer, a binder composition for firing, and a paste for firing. More specifically, it relates to an acrylic polymer blended in the binder composition for firing, a binder composition for firing containing the acrylic polymer, and a paste for firing containing the binder composition for firing.

Background Art

[0002] Regarding a binder composition for firing blended in a paste for firing for producing a sintered body of inorganic powder, Patent Document 1 discloses an acrylic polymer synthesized by polymerizing, in an organic solvent and in the presence of polyvinyl butyral, an acrylic monomer containing at least one of a carboxyl group-containing acrylic monomer and a nitrogen-containing acrylic monomer without reacting with polyvinyl butyral. A green sheet can be formed from a firing paste containing the binder composition for firing and inorganic powder, and a sintered body of inorganic powder can be produced by firing this green sheet. The sintered body of inorganic powder can be applied to electrodes, conductor wirings in various electronic devices, dielectric layers in multilayer capacitors, and the like.

[0003] According to the technique described in Patent Document 1, it is possible to utilize both the advantages of imparting high strength to a green sheet by polyvinyl butyral and good thermal decomposability by an acrylic polymer, and to provide a highly stable binder composition for firing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors conducted research and development to further improve the strength of the green sheet in order to further enhance the handling of the green sheet while maintaining the thermal decomposition properties of the firing binder composition.

[0006] The object of the present invention is to provide an acrylic polymer (A) that, when incorporated into a baking binder composition, can increase the strength of a green sheet made from a baking paste containing a baking binder composition without impairing the thermal decomposition properties of the baking binder composition; a baking binder composition containing this acrylic polymer (A); and a baking paste containing this baking binder composition. [Means for solving the problem]

[0007] The acrylic polymer (A) according to the first aspect of the present invention is an acrylic polymer (A) that is incorporated into a binder composition for firing, and has a constituent unit (a) represented by formula (1).

[0008] [ka]

[0009] In formula (1) above, R1 is a hydrogen atom or a methyl group, and R2 is a methylene group, an ethylene group, or an ethoxyethylene group.

[0010] A firing binder according to one aspect of the present invention contains the acrylic polymer (A).

[0011] A baking paste according to one aspect of the present invention contains the baking binder composition and an inorganic powder. [Effects of the Invention]

[0012] According to the present invention, an acrylic polymer can be incorporated into a baking binder composition to increase the strength of a green sheet made from a baking paste containing the baking binder composition without impairing the thermal decomposition properties of the baking binder composition. A baking binder composition containing this acrylic polymer, and a baking paste containing this baking binder composition are also provided. [Modes for carrying out the invention]

[0013] One embodiment of the present invention will be described below. Note that the following embodiment is merely one of many embodiments of the present invention, and the present invention can be modified in various ways depending on the design.

[0014] 1. Acrylic polymer The acrylic polymer (A) according to this embodiment is incorporated into a binder composition for firing. The acrylic polymer (A) is synthesized by polymerizing a polymerizable monomer containing a (meth)acrylic compound. A (meth)acrylic compound is a compound having a (meth)acryloyl group. In this specification, "(meth)acry-" means at least one of "acry-" and "methacrylic-", that is, it is a higher-level concept than "acry-" and "methacrylic-".

[0015] The acrylic polymer (A) has a constituent unit (a) represented by formula (1).

[0016] [ka]

[0017] In formula (1), R1 is a hydrogen atom or a methyl group, and R2 is a methylene group, an ethylene group, or an ethoxyethylene group.

[0018] According to this embodiment, by blending this acrylic polymer (A) into the firing binder composition, the strength of the green sheet produced from the firing paste containing the firing binder composition can be increased without impairing the thermal decomposability of the firing binder composition.

[0019] Structure become The percentage of the structural unit (a) is preferably 2% by mass or more and 20% by mass or less based on the acrylic polymer (A). Structure become If the percentage of the structural unit (a) is 2% by mass or more, the hardness of the green sheet can be particularly increased, and if this percentage is 20% by mass or less, the green sheet can have appropriate flexibility. For this reason, Structure become The strength of the green sheet can be particularly increased by the structural unit (a). The percentage of this structural unit (a) is more preferably 2.5% by mass or more, and even more preferably 5% by mass or more. Also, this Structure become The percentage of the structural unit (a) is more preferably 17.5% by mass or less, and even more preferably 15% by mass or less.

[0020] The acrylic polymer (A) may have a structural unit (b) represented by the formula (2).

[0021]

Chemical formula

[0022] In the formula (2), R3 is a hydrogen atom or a methyl group, and R4 is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms.

[0023] By the structural unit (b), the acrylic polymer (A) can have good properties as a binder such as moldability and thermal decomposability.

[0024] Structure become The percentage of the structural unit (b) is, for example, 5% by mass or more and 95% by mass or less based on the acrylic polymer (A). This Structure becomeThe percentage of unit (b) is more preferably 10% by mass or more, and even more preferably 15% by mass or more. become The percentage of unit (b) is more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0025] The acrylic polymer (A) may have a constituent unit (c) which is a residue of an unsaturated monomer having a carboxyl group. In this case, the affinity between the acrylic polymer (A) and the inorganic powder in the baking paste can be increased, making it easier to form the baking paste into a sheet and further increasing the strength of the green sheet.

[0026] Acrylic polymer (A) become If it has a unit (c), become The percentage of unit (c) is preferably 1% by mass or more and 10% by mass or less relative to the acrylic polymer (A). become The percentage of unit (c) is more preferably 2% by mass or more. become The percentage of unit (c) is more preferably 5% by mass or less.

[0027] The constituent unit (c) contains, for example, the constituent unit (C1) shown in formula (3).

[0028] [ka]

[0029] In formula (3), R5 is a hydrogen atom or a methyl group, and R6 is a hydrogen atom or a substituent represented by formula (4).

[0030] [ka]

[0031] In formula (4), R7 is a methylene group or an ethylene group, and R8 is a methylene group or an ethylene group.

[0032] Acrylic polymer (A) is composed of residues of unsaturated monomers containing hydroxyl groups. become The unit (d) may be included. In this case, the affinity between the acrylic polymer (A) and the inorganic powder in the firing paste can be increased, and intramolecular interactions can be enhanced, making it easier to form the firing paste into a sheet and further increasing the strength of the green sheet.

[0033] Acrylic polymer (A) become If it has a unit (d), become The percentage of unit (d) is preferably 30% by mass or more and 60% by mass or less relative to the acrylic polymer (A). become The percentage of unit (d) is more preferably 35% by mass or more, and even more preferably 40% by mass or more. become The percentage of unit (d) is more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0034] Structure become The unit (d) contains, for example, the constituent unit (D1) shown in formula (5).

[0035] [ka]

[0036] In formula (5), R9 is a hydrogen atom or a methyl group, R 10 These are hydroxyalkyl groups with 1 to 4 carbon atoms.

[0037] The acrylic polymer (A) may have constituent units (a) and (b), or constituent units (a), (b), and (c), or constituent units (a), (b), and (d), or constituent units (a), (b), (c), and (d).

[0038] Furthermore, the acrylic polymer (A) may or may not have constituent units other than constituent units (a), (b), (c), and (d) (hereinafter referred to as constituent unit (e)). If the acrylic polymer (A) has constituent unit (e), become The percentage of unit (e) is preferably 10% by mass or less relative to the acrylic polymer (A).

[0039] Examples of unsaturated ethylenic monomers capable of generating constituent unit (e) include benzyl (meth)acrylate, (3-phenoxyphenyl)methyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, glycidyl (meth)acrylate, 2-acetoacetoxyethyl (meth)acrylate, and allyl (meth)acrylate.

[0040] Furthermore, it is preferable that the acrylic polymer (A) does not have a constituent unit (e1) which is a polyfunctional monomer residue having two or more polymerizable unsaturated groups in one molecule. If the acrylic polymer (A) has a constituent unit (e1), become The percentage of unit (e1) is preferably 5% by mass or less relative to the acrylic polymer (A). In this case, excessive thickening of the baking binder composition containing the acrylic polymer (A) can be suppressed, and the moldability of the baking paste containing the baking binder composition can not be deteriorated. Furthermore, the acrylic polymer (A) does not have constituent units (e1), or the composition become When the percentage of unit (e1) is 5% by mass or less relative to the acrylic polymer (A), the flammability of the firing binder composition is further improved. This is presumed to be because a three-dimensional network is less likely to form in the framework of the acrylic polymer (A), thereby less likely to be inhibited during combustion.

[0041] Acrylic polymer (A) is synthesized, for example, by solution polymerization. For example, a reactive solution is prepared by combining polymerizable monomers, which are the raw materials for acrylic polymer (A), and a polymerization initiator in a solvent. The polymerizable monomers are monomers corresponding to each constituent unit of acrylic polymer (A). A chain transfer agent may also be added to the reactive solution. Acrylic polymer (A) is synthesized by polymerizing the polymerizable monomers by heating and stirring this reactive solution under an inert atmosphere.

[0042] The solvent is not particularly limited as long as it can dissolve or disperse the polymerizable monomer and the acrylic polymer (A). The solvent contains, for example, at least one selected from the group consisting of toluene, xylene, ethanol, 2-propanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, phenylpropylene glycol, phenyl glycol, texanol, benzyl alcohol, phenyldiglycol, terpineol, dihydroterpineol, dihydroterpinyl acetate, cyclohexanone, cyclopentanone, ethylene glycol, 1,4-butanediol, diethylene glycol, tetraethylene glycol, 1,3-butylene glycol, dipropylene glycol, tripylene glycol, octanediol, 2,4-diethyl-1,5-pentanediol, diethylene glycol monobutyl ether, butyl carbitol acetate, and solvent naphtha.

[0043] The polymerization initiator contains at least one selected from the group consisting of, for example, azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); 4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butyl peroxy-2-ethylhexanoate, cyclohexanone peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, and di-t-butyl peroxide.

[0044] The chain transfer agent contains at least one selected from the group consisting of, for example, n-dodecyl mercaptan, 2,4-diphenyl-4-methyl-1-pentene, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, and α-methylstyrene dimer.

[0045] The weight-average molecular weight of the acrylic polymer (A) is, for example, between 50,000 and 250,000. This weight-average molecular weight is the relative average weight molecular weight on a standard polystyrene basis, measured by gel permeation chromatography.

[0046] 2. Binder composition for firing The firing binder composition contains the above-mentioned acrylic polymer (A). The firing binder composition may further contain a solvent if necessary. The firing binder composition may also further contain additives such as dispersants and plasticizers if necessary.

[0047] The firing binder composition may further contain a polyfunctional amine compound (B). When the firing binder composition contains a polyfunctional amine compound (B), the strength of the green sheet may be further increased. This is because, in the process of preparing a firing paste from the firing binder composition and then producing a green sheet from the firing paste, the structure of the acrylic polymer (A) become It is presumed that a urethane bond is formed when the cyclocarbonate group in unit (a) reacts with the amino group in the polyfunctional amine compound (B), thereby creating a cross-linked structure.

[0048] An example of a structure formed by the reaction of an acrylic polymer (A) with a polyfunctional amine is shown in formula (6).

[0049] [ka]

[0050] In formula (6), R 11 Each is independently a hydrogen atom or a methyl group, R 12 Each of these is independently a methylene group, an ethylene group, or an ethoxyethylene group, and A is a residue of the polyfunctional amine compound (B).

[0051] Furthermore, since the polyfunctional amine compound (B) tends to leave residue when burned, it is generally undesirable to incorporate it into the calcination binder composition. However, in this embodiment, when the calcination binder composition contains the polyfunctional amine compound (B), if the polyfunctional amine compound (B) bonds with the cyclocarbonate group of the acrylic polymer (A) to form a urethane bond, less residue is left behind. Therefore, in this embodiment, the thermal decomposition properties of the calcination binder composition are less likely to be inhibited by the polyfunctional amine compound (B).

[0052] Furthermore, the reaction between the acrylic copolymer and the polyfunctional amine compound mainly occurs during the process of drying the baking paste to produce the green sheet. Therefore, gelation and thickening due to the reaction between the acrylic copolymer and the polyfunctional amine compound are unlikely to occur during the preparation of the baking binder composition and the baking paste. Consequently, problems such as deterioration of handling properties during the preparation of the baking binder composition and baking paste, and deterioration of moldability when producing the green sheet from the baking paste, are unlikely to occur.

[0053] The polyfunctional amine compound preferably contains an aliphatic diamine. In this case, the green sheet can have appropriate flexibility, which can further improve the strength of the green sheet.

[0054] The aliphatic diamine preferably contains at least one of ethylenediamine and hexamethylenediamine. In this case, the strength of the green sheet may be further improved.

[0055] The polyfunctional amine may contain three or more functional amines, and may, for example, polyethyleneimine. Polyethyleneimine can also further improve the strength of the green sheet.

[0056] The proportion of amino groups in the polyfunctional amine compound is preferably 95 mol% to 105 mol% relative to the cyclocarbonate groups of the acrylic polymer (A). If the proportion of the polyfunctional amine is 95 mol% or more, the strength of the green sheet may be further improved. Furthermore, if this proportion is 105 mol% or less, the thermal decomposition of the binder composition for firing is less likely to be inhibited. This proportion is more preferably 97 mol% or more, and even more preferably 99 mol% or more. Furthermore, this proportion is more preferably 103 mol% or less, and even more preferably 101 mol% or less.

[0057] 3. Paste for baking The baking paste contains a baking binder composition and inorganic powder.

[0058] The inorganic powder may contain appropriate powders depending on the application of the firing paste. For example, the inorganic powder may contain one or more materials selected from the group consisting of gold, copper, silver, nickel, palladium, alumina, zirconia, bismuth, titanium oxide, barium titanate, alumina nitride, silicon nitride, boron nitride, silicate glass, lead glass, CaO·Al2O3·SiO2-based inorganic glass, MgO·Al2O3·SiO2-based inorganic glass, and LiO2·Al2O3·SiO2-based inorganic glass.

[0059] The amounts of the baking binder composition and inorganic powder in the baking paste are preferably adjusted appropriately so as to maintain good applicability of the baking paste and good properties of the elements obtained by sintering the baking paste. For example, the amount of inorganic powder per 100 parts by mass of the baking binder composition is 20 parts by mass or more and 4000 parts by mass or less.

[0060] When using a baking paste, for example, the baking paste is first formed into a sheet. The method of forming the baking paste can be, for example, screen printing, dispensing, or doctor blade, but is not limited to these. The sheet-shaped baking paste is then dried by heating. At this time, the conditions for heating the baking paste for drying are, for example, a heating temperature of 100°C to 200°C and a heating time of 1 hour to 10 hours. The baking paste may also be first air-dried at room temperature and then further dried by heating. This causes the solvent in the baking binder composition to volatilize. Furthermore, if the baking binder composition contains a polyfunctional amine compound, a reaction between the acrylic polymer (A) and the polyfunctional amine compound proceeds. This produces a green sheet. In this embodiment, as already described, the green sheet can have high strength.

[0061] By heating this green sheet, the firing binder composition is thermally decomposed and the inorganic powder is sintered. This produces a sintered body of inorganic powder. At this time, the conditions for heating the firing paste for sintering are, for example, a heating temperature of 500°C to 1500°C and a heating time of 1 hour to 24 hours. In this embodiment, as already described, the firing binder composition can have good thermal decomposition properties, so the efficiency of producing the sintered body can be improved and impurities are less likely to remain in the sintered body.

[0062] The method for producing a sintered body using a firing paste is particularly suitable for producing dielectric layers in multilayer capacitors. However, the applications of the sintered body are not limited to dielectric layers; it can constitute appropriate elements such as electrodes, conductive wiring, and insulating layers. [Examples]

[0063] The following describes specific examples of this embodiment. However, this embodiment is not limited to the following examples.

[0064] 1. Polymer production A 1-liter four-necked flask equipped with a reflux condenser, thermometer, nitrogen purging tube, and stirrer was used as the reaction vessel. The raw materials, excluding the polymerization initiator, from the list in Table 1-3 were placed in the reaction vessel, and the temperature inside the vessel was raised under a nitrogen stream. When the temperature inside the vessel reached 80°C, the polymerization initiator was added, and the polymerization reaction was carried out at 80°C for 6 hours. After the reaction, the reaction vessel was cooled, and a solvent was added to obtain the polymer solution by ensuring the solution contained 30% by mass of non-volatile content.

[0065] The weight-average molecular weight in the polymer solution was measured. The weight-average molecular weight is the relative average molecular weight obtained by converting a calibration curve measured by gel permeation chromatography using a standard polymer. The measurement conditions are as follows. - Equipment name: Prominence HPLC system (manufactured by Shimadzu Corporation). - Columns: KF-805, KF-803, KF-801 (in series) (manufactured by Showa Denko Corporation). - Mobile phase: Tetrahydrofuran. -Flow rate: 1mL / min. - Detector: Differential refractive index detector. -Temperature: 40℃. - Molecular weight standard sample: Polystyrene.

[0066] In comparative manufacturing example 4, the weight-average molecular weight was not measured because the polymer solution gelled.

[0067] Furthermore, the details of the raw materials indicated by abbreviations in Table 1-3 are as follows. In Table 1-3, the composition become Unit (a), composition become Unit (b), composition become Units (c) and composition become The monomers corresponding to unit (d) are shown in columns (a), (b), (c), and (d), respectively. -CCMA: (2-oxo-1,3-dioxolan-4-yl)-methyl methacrylate. -MMA: Methyl methacrylate. -BMA: n-butyl methacrylate. -EHMA: 2-ethylhexyl methacrylate. -LMA: n-dodecyl methacrylate. -CHMA: Cyclohexyl methacrylate. -BA: n-butyl acrylate. -MAA: Methacrylic acid. -MOES: 2-methacryloyloxyethyl succinate. -AA: Acrylic acid. -AOES: 2-Acryloyloxyethyl succinate. -HEMA: 2-hydroxyethyl methacrylate. -HPMA: 2-hydroxypropyl methacrylate. -PEGDMA: Polyethylene glycol diacrylate #600. -PGM: Propylene glycol methyl ether. -MSD: α-methylstyrene dimer. -AIBN:2,2'-azobisisobutyronitrile.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] 2. Preparation of the green sheet The raw materials shown in Table 4-7 were mixed and stirred for 10 minutes using a stirring and defoaming device to prepare a baking paste. This baking paste was applied to a polyethylene terephthalate film and air-dried at room temperature for 12 hours. Subsequently, it was heated at 100°C for 60 minutes in Examples 7, 8, 15-18, 23-30 and Comparative Example 2, and at 150°C for 60 minutes in Examples 1-6, 9-14, 19-22, and Comparative Examples 1, 3, 4 and 5. This produced green sheets with a thickness of 200 μm for evaluation.

[0072] The details of the raw materials, which are indicated by abbreviations in Table 4-7, are as follows: -BT-01: Barium titanate, manufactured by Sakai Chemical Industry Co., Ltd. -PGM: Propylene glycol methyl ether. -BYK-102: Anionic polymerization initiator, manufactured by BYK-Chemie, catalog number BYK-102. -PEG400: Polyethylene glycol #400. -DOA: Bis(2-ethylhexyl) adipate. -HT-510: Polyethylene glycol-polypropylene glycol alkyl ether. Manufactured by NOF Corporation, product number HT-510. -PVB: Polyvinyl butyral. Manufactured by Sekisui Chemical Co., Ltd., product name: S-Rec BH-3. -PEI: Polyethyleneimine. Manufactured by Nippon Shokubai Co., Ltd., product name: Epomin SP-003.

[0073] 3. Evaluation (1) Tensile strength A sample measuring 1 cm wide and 6 cm long was cut from the prepared green sheet. The tensile strength (maximum stress) of the sample was measured using a tensile testing machine (Shimadzu Corporation, model AGS-1kNX) at a tensile speed of 20 mm / min.

[0074] (2) Reactivity of polyfunctional amine compound (B) For each of Examples 2, 4, 6, 8, 10, 12, 14, 15, 16, and 18-30, which used polyfunctional amine compound (B), infrared absorption analysis of the green sheets was performed under ambient temperature conditions of 25°C. In addition, a mixture of the polymer solution and polyfunctional amine compound (B) was prepared from the raw materials of the green sheets. Infrared absorption analysis was also performed on this mixture under ambient temperature conditions of 25°C.

[0075] As a result, the infrared absorption spectrum of the green sheet showed 1790 cm⁻¹. -1 The intensity of the absorption peak in the vicinity is 1790 cm⁻¹ in the mixture's infrared absorption spectrum. -1 The intensity of the absorption peaks in the vicinity was evaluated as "A" if it was less than 10%, "B" if it was between 10% and 20%, and "C" if it was greater than 20%.

[0076] (3) Firing properties Samples obtained by drying the polymer solution used to prepare the green sheet and allowing the solvent to evaporate were measured using a differential thermal and thermogravimetric analyzer (TG-DTA8122, manufactured by Rigaku Corporation) under air conditions, a heating rate of 10°C / min, and a temperature range of 25°C to 500°C.

[0077] As a result, the weight loss rate of the sample at 500°C, based on the weight of the sample at 25°C, was evaluated as follows: "A" if 99% or more, "B" if 98% or more but less than 99%, "C" if 95% or more but less than 98%, and "D" if less than 95%.

[0078] The results are shown in Table 4-7.

[0079] [Table 4]

[0080] [Table 5]

[0081] [Table 6]

[0082] [Table 7]

[0083] As shown in the results above, in Examples 1 to 30, the structure shown in formula (1) become Because a binder composition for firing containing an acrylic polymer (A) having unit (a) is used, it was found that the green sheet has excellent strength, and the binder composition for firing has excellent firing properties.

[0084] In Comparative Examples 1 to 3, the structure shown in formula (1) becomeBecause a binder composition for firing containing a polymer without unit (a) was used, the firing properties of the polymer were excellent, but the strength of the green sheet was found to be inferior to that of any of the other examples. In addition, Comparative Example 4 had a cross-linked structure that was resistant to thermal decomposition during green sheet formation, so the firing properties of the polymer were somewhat inferior. In Comparative Example 5, polyvinyl butyral was included as a binder, so the strength of the green sheet was excellent, but the firing properties were low, so it was found that the usage conditions when using it as a binder for firing were limited.

Claims

1. This is a binder composition for firing containing an acrylic polymer (A), The acrylic polymer (A) comprises a structural unit (a) represented by formula (1) and a structural unit (b) represented by formula (2). 【Chemistry 1】 【Chemistry 2】 In the above formula (1), R １ R is a hydrogen atom or a methyl group, ２ This is a methylene group, an ethylene group, or an ethoxyethylene group. In formula (2) above, R3 is a hydrogen atom or a methyl group, and R4 is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms. The percentage of the aforementioned constituent unit (a) is 2% by mass or more and 20% by mass or less relative to the acrylic polymer (A). The percentage of the constituent unit (b) is 5% by mass or more and 95% by mass or less relative to the acrylic polymer (A). Binder composition for firing.

2. The acrylic polymer (A) further comprises a constituent unit (c) which is a residue of an unsaturated monomer having a carboxyl group. The baking binder composition according to claim 1.

3. The constituent unit (c) contains the constituent unit (C1) represented by formula (3), 【Transformation 3】 In formula (3) above, R5 is a hydrogen atom or a methyl group, and R6 is a hydrogen atom or a substituent represented by formula (4). 【Chemistry 4】 In formula (4) above, R7 is a methylene group or an ethylene group, and R8 is a methylene group or an ethylene group. The baking binder composition according to claim 2.

4. The acrylic polymer (A) further comprises a constituent unit (d) which is a residue of an unsaturated monomer containing a hydroxyl group. A binder composition for firing according to any one of claims 1 to 3.

5. The constituent unit (d) contains a constituent unit (D1) represented by the following formula (5), 【Transformation 5】 In formula (5) above, R9 is a hydrogen atom or a methyl group, and R10 is a hydroxyalkyl group having 1 to 4 carbon atoms. The baking binder composition according to claim 4.

6. Further comprising a polyfunctional amine compound (B), A binder composition for firing according to any one of claims 1 to 5.

7. The polyfunctional amine compound (B) contains an aliphatic diamine, The baking binder composition according to claim 6.

8. The aliphatic diamine contains at least one of ethylenediamine and hexamethylenediamine. The baking binder composition according to claim 7.

9. The polyfunctional amine compound (B) contains polyethyleneimine, The baking binder composition according to claim 6.

10. A binder composition for firing according to any one of claims 1 to 9, and an inorganic powder, Paste for baking.

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