JP2018165231A - Binder for production of mineral sintered bodies - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder for the production of mineral sintered bodies that has excellent pyrolytic properties; when used as a binder for making a ceramic green sheet, achieves high porosity; and yields a ceramic green sheet that resists cracking and other trouble when producing a sintered body, and provide a slurry for the production of mineral sintered bodies comprising the binder for the production of mineral sintered bodies, a ceramic green sheet and a fuel cell power cell.SOLUTION: A binder for the production of mineral sintered bodies contains a binder resin composition in which a difference between 5 wt.% weight loss temperature and 95 wt.% weight loss temperature is 230°C or more when the temperature is increased by 10°C/min.SELECTED DRAWING: None

Description

The present invention is a ceramic that is excellent in thermal decomposability and can realize a high porosity when used as a binder for producing a ceramic green sheet, and is less susceptible to defects such as cracks when producing a sintered body. The present invention relates to a binder for producing an inorganic sintered body from which a green sheet can be obtained. The present invention also relates to an inorganic sintered compact manufacturing slurry, a ceramic green sheet, and a fuel cell power generation cell using the inorganic sintered compact manufacturing binder.

Solid oxide fuel cells (SOFCs) are the next generation with low environmental impact because of their high power generation efficiency and the ability to use a variety of fuels among the various fuel cells that convert chemical energy into battery energy. It is attracting attention as a power generation device.
The SOFC power generation cell has a laminated structure in which an air electrode having a porous structure is formed on one surface of an inorganic sintered body such as a solid electrolyte layer and a fuel electrode having a porous structure is formed on the other surface. doing.

As the solid electrolyte for SOFC, ceramic raw material powder having excellent oxygen ion conductivity is used. As such ceramic raw material powder, a zirconia-based material such as yttria-stabilized zirconia (YSZ) or a ceria-based material is widely used because of its excellent chemical stability and mechanical strength.

In the production of SOFC, a slurry is prepared by uniformly mixing a pore-forming agent such as carbon powder, ceramic raw material powder, a binder, a dispersant and an organic solvent with a mixing device such as a ball mill, and applying this slurry to a support. A ceramic green sheet is produced by molding into a sheet shape, and the green sintered sheets are laminated and fired to produce an inorganic sintered body.

Binders used for such ceramic green sheets are required to have higher performance than conventional in terms of imparting sheet strength when made into ceramic green sheets and thermal decomposability during firing. In addition, in order to stack a plurality of thin green sheets, it is important that the adhesiveness during hot pressing is good.

On the other hand, for example, Patent Document 1 discloses a method for producing a ceramic green sheet having excellent adhesiveness during hot pressing by using a mixture of polyvinyl acetal resins having different degrees of polymerization.
However, when polyvinyl acetal is used alone as the binder resin, the sheet strength is high, but the thermal decomposability is poor, so there is a problem that a part of the binder does not decompose and burn and remains as a residual carbide in the sintered body. . In addition, in the fuel cell, it is necessary to increase the porosity of the inorganic sintered body in order to improve the power generation efficiency. However, if the porosity is increased, the strength of the fuel cell decreases, so that it is rapidly decomposed in the firing process. When the gas is generated, there is a problem that cracks, warpage, swelling, and the like may occur in the molded body, thereby reducing the productivity of the fuel cell.

On the other hand, Patent Document 2 discloses a method using an acrylic resin having excellent thermal decomposability. However, when an acrylic resin is used, the residual carbide after firing is reduced, but the ceramic green sheet produced using the acrylic resin as a binder is not sufficient in strength and flexibility, and the process of drying the green sheet and thereafter When performing other processes, there was a problem that cracks were likely to occur in the green sheet.

Japanese Patent No. 3739237 Japanese Patent Laid-Open No. 6-237054

The present invention is a ceramic that is excellent in thermal decomposability and can realize a high porosity when used as a binder for producing a ceramic green sheet, and is less susceptible to defects such as cracks when producing a sintered body. It aims at providing the binder for inorganic sintered compact manufacture from which a green sheet is obtained. Another object of the present invention is to provide a slurry for producing an inorganic sintered body, a ceramic green sheet and a fuel cell power generation cell using the inorganic sintered body producing binder.

The present invention relates to a binder for producing an inorganic sintered body containing a binder resin composition having a difference between a 5 wt% weight loss temperature and a 95 wt% weight loss temperature of 230 ° C or higher when the temperature is raised at 10 ° C / min. It is.
The present invention is described in detail below.

By using a binder containing a binder resin composition in which 5 wt% weight loss temperature and 95 wt% weight loss temperature have a predetermined relationship as a binder for producing an inorganic sintered body, When used as a binder for producing a sheet, it has been found that by performing a degreasing and firing step, it is possible to obtain a sintered body having a high porosity and hardly causing defects such as cracks. The invention has been completed.

The binder for producing an inorganic sintered body of the present invention contains a binder resin composition.
The binder resin composition has a difference between the 5 wt% weight loss temperature and the 95 wt% weight loss temperature of 230 ° C. or more when the temperature is raised at 10 ° C./min.
Since the difference between the 5 wt% weight loss temperature and the 95 wt% weight loss temperature is 230 ° C. or more, the binder does not rapidly decompose in the degreasing and firing step when manufacturing the sintered body, and the volume Generation | occurrence | production of the defect of the inorganic sintered compact sheet | seat by the crack accompanying a shrinkage | contraction and a crack can be prevented. Further, it is possible to prevent the laminate from being peeled off due to the rapid generation of decomposition gas.
The difference between the 5 wt% weight loss temperature and the 95 wt% weight loss temperature is more preferably a lower limit of 270 ° C., a preferred upper limit of 350 ° C., and a more preferred upper limit of 300 ° C.
The 5% by weight weight loss temperature is a temperature at which 5% by weight is lost when the temperature is increased from room temperature to 10 ° C./min in an air atmosphere by a thermogravimetric analyzer. The 95 wt% weight loss temperature is the temperature at which 95 wt% is lost when the temperature is raised from room temperature at 10 ° C / min. Specifically, it can be determined from a thermogravimetric decrease curve obtained when the temperature is raised from room temperature at 10 ° C./min.

The binder resin composition has a preferable lower limit of 5% by weight weight loss temperature of 200 ° C. and a preferable upper limit of 350 ° C. when the temperature is raised at 10 ° C./min.
If the 5 wt% weight loss temperature is not less than the above preferable lower limit and not more than the above preferable upper limit, the temperature required for decomposing the binder by 5 wt% can be lowered, so that the energy used can be kept low. In addition, defects such as cracks can be effectively suppressed in the degreasing process.
The 5 wt% weight loss temperature has a more preferable lower limit of 250 ° C and a more preferable upper limit of 300 ° C.

The binder resin composition has a preferable lower limit of 95% by weight weight loss when heated at 10 ° C./min to 450 ° C., a more preferable lower limit to 500 ° C., a preferable upper limit to 600 ° C., and a more preferable upper limit to 550 ° C. is there.

The binder resin composition includes, for example, polyvinyl butyral and polyvinyl acetal resins such as polyvinyl acetoacetal, polyvinyl alcohol resins such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxy as binder resins. Cellulose resins such as propylmethylcellulose and cellulose acetate phthalate, (meth) acrylic resins such as poly (meth) acrylic acid esters, nitrile resins such as polyacrylonitrile and polymethacrylonitrile, urethane resins such as polyurethane, polyethylene , Vinyl resins such as polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyvinyl fluoride, vinyl acetate, It includes those containing rubber resin such as Ren butadiene rubber.

The binder resin composition preferably contains a polyvinyl acetal resin, and further preferably contains a (meth) acrylic acid resin.
The binder for producing an inorganic sintered body according to the present invention contains a polyvinyl acetal resin and a (meth) acrylic acid resin, so that when the ceramic green sheet is produced, the mechanical strength of the ceramic green sheet obtained and Adhesiveness can be improved. In addition, when the ceramic green sheet is fired, it is excellent in thermal decomposability and hardly decomposes rapidly, thereby preventing cracks and cracks associated with volume shrinkage and suppressing sheet peeling.
In the present invention, the polyvinyl acetal resin means a polyvinyl butyral component contained in a composite resin of polyvinyl butyral and poly (meth) acrylic acid described later, in addition to the polyvinyl acetal resin single component.
In addition to the (meth) acrylic resin single component, the (meth) acrylic resin is a poly (meth) acrylic acid contained in a composite resin of polyvinyl butyral and poly (meth) acrylic acid described later. Means ingredients.

The polyvinyl acetal resin has a preferable lower limit of the polymerization degree of 600 and a preferable upper limit of 5000.
When the polymerization degree of the polyvinyl acetal resin is 600 or more, the mechanical strength of the obtained ceramic green sheet can be sufficiently improved. When the degree of polymerization of the polyvinyl acetal resin is 5000 or less, the solution viscosity can be made suitable when acetalizing polyvinyl alcohol.
The more preferable lower limit of the degree of polymerization of the polyvinyl acetal resin is 1000, and the more preferable upper limit is 4500.

Degree of acetalization of the polyvinyl acetal resin (in the present specification, when the acetal group is an acetoacetal group, it is also called an acetoacetalization degree, and when the acetal group is a butyral group, it is also called a butyralization degree. ) Has a preferable lower limit of 40 mol% and a preferable upper limit of 80 mol%, regardless of whether the aldehyde is used alone or in combination of two or more. When the degree of acetalization is 40 mol% or more, sufficient flexibility can be imparted to the ceramic green sheet without aggregation of the polyvinyl acetal resin. When the degree of acetalization is 80 mol% or less, the mechanical strength of the obtained ceramic green sheet can be sufficiently improved.
A more preferable lower limit of the degree of acetalization is 55 mol%, and a more preferable upper limit is 75 mol%.
In addition, about the calculation method of the degree of acetalization, since the acetal group of the polyvinyl acetal resin is obtained by acetalizing two hydroxyl groups of polyvinyl alcohol, a method of counting the two acetalized hydroxyl groups Is adopted.

The minimum with the preferable amount of hydroxyl groups of the said polyvinyl acetal type resin is 20 mol%, and a preferable upper limit is 55 mol%. When the hydroxyl group content is 20 mol% or more, the mechanical strength of the obtained ceramic green sheet can be improved. When the hydroxyl group content is 55 mol% or less, the adhesiveness of the obtained ceramic green sheet under high humidity may be lowered.
A more preferred lower limit of the hydroxyl group content is 25 mol%, and a more preferred upper limit is 45 mol%.

The minimum with the preferable amount of acetyl groups of the said polyvinyl acetal type resin is 0.5 mol%, and a preferable upper limit is 20 mol%. When the acetyl group amount is 0.5 mol% or more, the mechanical strength of the obtained ceramic green sheet can be sufficiently improved. When the acetyl group content is 20 mol% or less, the adhesiveness of the obtained ceramic green sheet can be made suitable.
The minimum with said more preferable amount of acetyl groups is 1.0 mol%, and a more preferable upper limit is 15 mol%.

The polyvinyl acetal resin is preferably a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol having a saponification degree of 80 mol% or more. By using such a polyvinyl acetal resin, the stability of the binder resin composition can be improved and excellent mechanical strength can be expressed over a long period of time.
If the degree of saponification of polyvinyl alcohol is less than 80 mol%, the solubility of polyvinyl alcohol in water may decrease, making acetalization difficult. Moreover, since the amount of hydroxyl groups of polyvinyl alcohol is small, the acetalization reaction may not proceed easily. A more preferred lower limit of the degree of saponification of polyvinyl alcohol is 85 mol%.

The polyvinyl acetal resin may have a structural unit having a modifying group in which a hydroxyl group is modified.
Examples of the modifying group include those modified with polyethylene oxide, polydimethylsiloxane, and the like.

The content of the structural unit having the modifying group in the polyvinyl acetal resin (modifying group amount) is preferably 0.1 mol% at the lower limit and 50 mol% at the upper limit.

The method for acetalization is not particularly limited, and a conventionally known method can be used. Examples thereof include a method of adding an aldehyde to an aqueous solution of polyvinyl alcohol in the presence of an acid catalyst such as hydrochloric acid.
The aldehyde is not particularly limited. For example, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butyraldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, furfural , Glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde and the like. Of these, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), butyraldehyde, cyclohexylaldehyde, and benzaldehyde are preferable in terms of productivity, property balance, and the like. These aldehydes may be used alone or in combination of two or more.

The preferable lower limit of the content of the polyvinyl acetal resin in the binder resin composition is 10% by weight, and the preferable upper limit is 90% by weight.
When the content of the polyvinyl acetal resin is 10% by weight or more, the adhesion of the obtained ceramic green sheet can be sufficiently improved. When the content of the polyvinyl acetal resin is 90% by weight or less, the peelability can be improved. A more preferred lower limit is 20% by weight, a still more preferred lower limit is 30% by weight, a more preferred upper limit is 80% by weight, and a still more preferred upper limit is 70% by weight.

The binder resin composition preferably contains a (meth) acrylic acid resin.
The (meth) acrylic acid resin is obtained by polymerizing (meth) acrylic acid as a monomer.
The (meth) acrylic acid preferably includes a (meth) acrylic acid ester having an alkyl group, and more preferably has a (meth) acrylic acid ester having an alkyl group having 1 to 10 carbon atoms. That is, the (meth) acrylic acid resin preferably has a (meth) acrylic acid ester unit having an alkyl group.
Examples of the alkyl group include methyl group, ethyl group, propyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, and n-hexyl group. , Isohexyl group, sec-hexyl group, tert-hexyl group, n-heptyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, n-octyl group, isooctyl group, sec-octyl group, tert-octyl group, n-nonyl group, isononyl group, sec-nonyl group, tert-nonyl group, n-decyl group, isodecyl group, sec-decyl group, tert-decyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, etc. Is mentioned.
The alkyl group may have an aryl group as a substituent, and specific examples include a benzyl group, a methylbenzyl group, a phenethyl group, and a naphthylmethyl group.

Specific examples of the (meth) acrylic acid ester having an alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) ) Acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate Decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, and the like. Among them, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, butyl (meth) acrylate such as t-butyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate is preferably used.
In the present specification, the (meth) acrylate is a general term for acrylate and methacrylate.

The content of the (meth) acrylic acid ester unit having the alkyl group in the (meth) acrylic acid resin is preferably 10% by weight in the preferred lower limit and 90% by weight in the preferred upper limit.

The (meth) acrylic acids preferably contain 90% by weight or more of methacrylic acid, and more preferably 90% by weight or more of monofunctional methacrylic acid ester. Thus, when used as a binder for a ceramic green sheet, the decomposability at the time of firing becomes high, and a binder with little residual carbide can be obtained. Moreover, when it is set as a slurry, it can be set as a moderate viscosity.

The (meth) acrylic acid constituting the (meth) acrylic resin is a (meth) acrylic acid ester (hereinafter referred to as a low Tg (meth) acrylic acid ester) whose glass transition temperature of the homopolymer is 25 ° C. or lower. (Also referred to as).
Examples of the (meth) acrylic acid ester having a glass transition temperature of 25 ° C. or less as the homopolymer include n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) ) Acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isotetradecyl (meth) acrylate, and the like.
In addition, the glass transition temperature of the said homopolymer means the glass transition temperature of the homopolymer with a polymerization degree of 3000-4000.

The content of the low Tg (meth) acrylic acid ester unit in the (meth) acrylic resin is preferably 5% by weight, more preferably 10% by weight, more preferably 20% by weight, and a preferred upper limit. 95% by weight, a more preferred upper limit is 80% by weight, and a still more preferred upper limit is 50% by weight.
When the content of the low Tg (meth) acrylic acid ester unit is not less than the above preferable lower limit and not more than the above preferable upper limit, the glass transition temperature of the (meth) acrylic acid resin can be sufficiently lowered. When used as a binder for ceramic green sheets, the binder can be made excellent in decomposability during firing.

The (meth) acrylic acids constituting the (meth) acrylic resin may be used alone as long as the glass transition temperature of the (meth) acrylic resin is 0 to 110 ° C. You may use the above together.
In addition, when the said (meth) acrylic acid consists of 2 or more types, as a method of making the glass transition temperature of the said (meth) acrylic acid-type resin into the range of 0-110 degreeC, the following (1) Formula is shown, for example. It is preferable to select (meth) acrylic acids so as to satisfy.

0 ≦ W ₁ / Tg ₁ + W ₂ / Tg ₂ +... ≦ 0.0125 (1)

In the formula (1), W ₁ , W ₂ ... Indicate mass fractions of (meth) acrylic acid 1, (meth) acrylic acid 2,. Note that W ₁ + W ₂ +.
Tg ₁ , Tg ₂ ... Are the glass transition temperatures (° K) of homopolymers of (meth) acrylic acid 1, (meth) acrylic acid 2,. Indicates.

The (meth) acrylic acid may contain one having at least one polar group selected from the group consisting of a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and an ether group in the molecule. By containing the (meth) acrylic acid having the polar group, a binder having excellent dispersibility of the inorganic fine particles can be obtained.
Specifically, for example, (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylamide, amino (meth) acrylate Examples include (meth) acrylic acid esters having a polyethylene glycol chain in the ester side chain, such as ethyl, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, and methoxytriethylene glycol methacrylate. It is done.

Moreover, by containing the (meth) acrylic acid which has a polar group in the said molecule | numerator, the oxygen content in a binder becomes high and it can be set as the binder excellent in residual carbon property.
The content of the (meth) acrylic acid unit having a polar group in the molecule in the (meth) acrylic resin is preferably 3% by weight, more preferably 10% by weight, and preferably 50% by weight. A more preferred upper limit is 30% by weight.

Moreover, it is preferable that the said (meth) acrylic-acid type resin contains 5-50 weight% of (meth) acrylic acid units which have an epoxy group, and it is more preferable to contain 10-30 weight%.
Furthermore, the (meth) acrylic acid-based resin preferably contains 1 to 30% by weight, more preferably 5 to 20% by weight, of a (meth) acrylic acid unit having a carboxyl group or an amide group.

The glass transition temperature of the (meth) acrylic acid resin has a preferable lower limit of 0 ° C. and a preferable upper limit of 110 ° C.
When the glass transition temperature of the (meth) acrylic resin is 0 ° C. or higher, when used as a binder for a ceramic green sheet, sufficient sheet strength can be imparted as having excellent flexibility. Moreover, the difference in glass transition temperature from the polyvinyl acetal resin does not become too large, and uniform physical properties can be exhibited. When the glass transition temperature of the (meth) acrylic resin is 110 ° C. or lower, the plasticity of the green sheet can be sufficiently improved, and the adhesiveness during hot pressing and the processability of the entire process can be improved.
The minimum with a more preferable glass transition temperature of the said (meth) acrylic-acid-type resin is 20 degreeC, and a more preferable upper limit is 70 degreeC.
The glass transition temperature of the (meth) acrylic resin is such that when the binder resin composition contains a composite resin in which polyvinyl butyral and (meth) acrylic resin are combined, the composite resin is subjected to differential scanning calorimetry. In this case, it can be measured by excluding the glass transition temperature derived from polyvinyl butyral estimated from the glass transition temperature of the homopolymer.

The difference between the glass transition temperature of the (meth) acrylic resin and the glass transition temperature of the polyvinyl acetal resin is preferably 3 to 40 ° C, more preferably 5 to 30 ° C.
Within the above range, a resin having a low glass transition temperature can relieve stress, and when used as a binder for a ceramic green sheet, sufficient flexibility can be imparted.
Moreover, even if a stress or the like acts during punching or heating and pressing after lamination, the stress is effectively absorbed, so that the generation of cracks in the ceramic green sheet can be effectively suppressed.

The content of the (meth) acrylic acid resin contained in the binder resin composition is not particularly limited because it is designed according to the use, but the preferred lower limit is 10% by weight and the preferred upper limit is 90% by weight.
When the content of the (meth) acrylic acid resin is 10% by weight or more, the decomposability at the time of firing can be improved, and the residual carbides contained in the ceramic can be reduced. When the content of the (meth) acrylic acid resin is 90% by weight or less, the strength of the obtained ceramic green sheet can be made sufficient, rapid decomposition during firing hardly occurs, and volume shrinkage Generation | occurrence | production of the defect of an inorganic sintered compact sheet | seat, such as a crack accompanying a crack and a crack, can be prevented.
The content of the (meth) acrylic resin is more preferably a lower limit of 20% by weight, a more preferable upper limit of 80% by weight, a still more preferable lower limit of 30% by weight, a still more preferable upper limit of 70% by weight, and a particularly preferable lower limit of 40%. % By weight, with a particularly preferred upper limit being 60% by weight.

The binder resin composition may include a mixed resin of a polyvinyl acetal resin and a (meth) acrylic acid resin, and a composite resin constituted by combining polyvinyl butyral and poly (meth) acrylic acid. It may be included. Moreover, although the said composite resin and the polyvinyl acetal type resin and / or (meth) acrylic-acid type resin which are not compounded may be included, it is preferable to contain a composite resin. By containing the composite resin, mechanical strength and adhesiveness can be further improved.
The composite resin is not particularly limited as long as polyvinyl butyral and poly (meth) acrylic acid are bonded to each other. For example, polyvinyl butyral and poly (meth) acrylic acid may be linearly bonded, and polyvinyl butyral or poly (meth) acrylic acid constituting the main chain may have a side chain different from the main chain. The polyvinyl butyral or poly (meth) acrylic acid to be formed may be branched. In addition, polyvinyl butyral and poly (meth) acrylic acid are linearly bonded to each other, and polyvinyl butyral or poly (meth) acrylic acid constituting a side chain different from the main chain portion is bonded. Also good.
In the present invention, the poly (meth) acrylic acid constituting the composite resin means a structure obtained by polymerizing the monomer (meth) acrylic acid.

A preferable lower limit of the degree of polymerization of the polyvinyl butyral is 600, and a preferable upper limit is 4000.
When the polymerization degree of the polyvinyl butyral is 600 or more, the sheet strength of the ceramic green sheet to be obtained can be improved, and the generation and breakage of cracks can be suppressed. When the degree of polymerization of the polyvinyl butyral is 4000 or less, the flexibility can be sufficient and the adhesiveness can be improved. In addition, adhesion failure such as delamination can be prevented in the laminating process by hot pressing.
When the degree of polymerization of the polyvinyl butyral is not less than the above preferable lower limit and not more than the above preferable upper limit, the viscosity when it is made into a slurry is improved, and the dispersibility of the ceramic powder is improved and applied to the support. The coating unevenness can be suppressed and a homogeneous ceramic green sheet can be produced.
A more preferable lower limit of the degree of polymerization of the polyvinyl butyral is 800, and a more preferable upper limit is 3500.

The polyvinyl butyral has a vinyl acetate unit, a vinyl alcohol unit, and a vinyl butyral unit that are usually contained in polyvinyl butyral.

The content of the vinyl alcohol unit (hydroxyl group amount) in the polyvinyl butyral is preferably 20 mol%, and preferably 40 mol%.
When the amount of the hydroxyl group is 20 mol% or more, the flexibility of the sheet when it is made into a green sheet is made suitable, and the peelability from the support can be optimized. Further, the strength of the obtained sheet can be made sufficient, and the dispersibility of the ceramic powder can be improved. When the amount of the hydroxyl group is 40 mol% or less, sufficient flexibility is obtained, the viscosity when it is made into a slurry is suitable, the coating unevenness is suppressed when applied to a support, and a homogeneous ceramic green sheet Can be produced.
The hydroxyl group content of the polyvinyl butyral is more preferably a lower limit of 25 mol% and a more preferable upper limit of 35 mol%.

The content of vinyl butyral units in the polyvinyl butyral (degree of butyralization) is preferably 60 mol%, and preferably 80 mol%.
When the degree of butyralization is 60 mol% or more, sufficient flexibility is obtained, the viscosity when made into a slurry is suitable, and uneven coating is suppressed when applied to a support, and a homogeneous ceramic green A sheet can be produced. When the degree of butyralization is 80 mol% or less, the strength of the resulting sheet can be sufficiently improved.
A more preferable lower limit of the degree of butyralization is 65 mol%, and a more preferable upper limit is 75 mol%.

The content (acetyl group amount) of vinyl acetate units in the polyvinyl butyral is not particularly limited, but it is preferably 30 mol% or less in view of sheet strength when used as a raw material for ceramic green sheets.
When the amount of the acetyl group is 30 mol% or less, the glass transition temperature of polyvinyl butyral is sufficient, the flexibility does not become too high, and the handling properties of the green sheet can be improved.

As for the content rate of the polyvinyl butyral contained in the said composite resin, a preferable minimum is 10 weight% and a preferable upper limit is 90 weight%.
When the content of the polyvinyl butyral is 10% by weight or more, the sheet strength of the obtained ceramic green sheet can be improved, and sufficient flexibility can be imparted. When the content of the polyvinyl butyral is 90% by weight or less, the decomposability at the time of firing is sufficient, and residual carbides contained in the ceramic can be reduced.
The content of the polyvinyl butyral is more preferably a lower limit of 20% by weight, a more preferable upper limit of 80% by weight, a still more preferable lower limit of 30% by weight, a still more preferable upper limit of 70% by weight, a particularly preferable lower limit of 40% by weight, A particularly preferred upper limit is 60% by weight.

As said poly (meth) acrylic acid, the structure similar to the said (meth) acrylic-acid-type resin is mentioned.

As for the content ratio of the poly (meth) acrylic acids contained in the composite resin, a preferable lower limit is 10% by weight, and a preferable upper limit is 90% by weight.
When the content ratio of the poly (meth) acrylic acid is 10% by weight or more, the decomposability at the time of firing can be improved and the residual carbides contained in the ceramic can be reduced. When the content ratio of the poly (meth) acrylic acid is 90% by weight or less, the sheet strength of the obtained ceramic green sheet can be sufficient, rapid decomposition during firing hardly occurs, and volume shrinkage occurs. Generation | occurrence | production of the defect of the inorganic sintered compact sheet | seat by the accompanying crack and a crack can be prevented.
The content ratio of the poly (meth) acrylic acids is more preferably a lower limit of 20% by weight, a more preferable upper limit of 80% by weight, a still more preferable lower limit of 30% by weight, a still more preferable upper limit of 70% by weight, and a particularly preferable lower limit of 40% by weight. %, And a particularly preferred upper limit is 60% by weight.

Moreover, when the binder resin composition contains a composite resin composed of polyvinyl butyral and poly (meth) acrylic acid bonded, the content of the composite resin in the binder resin composition has a preferred lower limit. 10%, a more preferred lower limit is 20%, a preferred upper limit is 90%, and a more preferred upper limit is 80%.
When the content of the composite resin is not less than the preferable lower limit and not more than the preferable upper limit, a structure having a (meth) acrylic acid resin as a dispersed phase is formed in the polyvinyl acetal resin as a continuous phase. It will be easy. Moreover, the dispersibility of the (meth) acrylic acid resin as a dispersed phase can be improved, and the mechanical strength of the ceramic green sheet obtained can be improved.

Although there is no restriction | limiting in particular as the molecular weight of the said composite resin, The minimum with a preferable number average molecular weight (Mn) is 10,000, and a preferable upper limit is 400,000.
A preferable lower limit of the weight average molecular weight (Mw) of the composite resin is 20,000, and a preferable upper limit is 800,000.
The preferable lower limit of the molecular weight distribution (Mw / Mn) of the composite resin is 2.0, the more preferable lower limit is 4.0, the preferable upper limit is 40, and the more preferable upper limit is 20.
When Mn, Mw, and Mw / Mn are within such ranges, when the composite resin is used as a binder for a ceramic green sheet, the sheet strength and flexibility can be balanced. Moreover, since the slurry viscosity does not become too high and the dispersibility of the inorganic powder is improved, a uniform ceramic green sheet can be formed, which is preferable.

The composite resin may further have a resin composed of another monomer.
When the composite resin has a resin composed of the other monomer, intermolecular interaction of the obtained resin composition is increased, and a ceramic green sheet having high sheet strength is formed by using the resin composition as a binder. can do. In addition, when the other monomer has a polar group, the polar group and the surface of the inorganic powder cause an interaction such as a hydrogen bond, thereby improving the dispersibility of the inorganic powder in the resulting slurry and Even when no agent is blended, a uniform ceramic green sheet can be formed. Furthermore, when the other monomer has a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, and an ether group, the oxygen content in the binder is increased, and radicals effective for thermal decomposition are generated. As a result, it is possible to help burn the binder and obtain a green sheet with very little residual carbide.

The other monomer is not particularly limited, but includes at least one polar group selected from the group consisting of a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and an ether group in the molecule, and one olefinic double bond. Monomers having are preferred. Examples of such monomers include crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, allyl alcohol, vinyl ether, allylamine, and the like. Among these other monomers, when a ceramic green sheet is produced using a binder containing the resulting composite resin, a higher sheet strength can be obtained. Therefore, a monomer having a carboxyl group in the molecule, A monomer having a hydroxyl group is more preferable.

The content of the resin composed of other monomers contained in the composite resin is not particularly limited because it is designed according to the use, but is preferably 20% by weight or less, and preferably 10% by weight based on the entire composite resin. The following is more preferable, and 5% by weight or less is more preferable.

The method for producing the composite resin is not particularly limited. For example, a method in which a mixed monomer containing the (meth) acrylic acid is radically polymerized in the presence of a polymerization initiator in an environment where polyvinyl butyral is present, etc. Is mentioned.
The said polymerization method is not specifically limited, For example, conventionally well-known polymerization methods, such as solution polymerization, emulsion polymerization, suspension polymerization, block polymerization, are mentioned.
The solvent used for the solution polymerization is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethyl sulfoxide, ethanol, acetone, diethyl ether, tetrahydrofuran, and a mixed solvent thereof.

Specific examples of the operation method for producing the composite resin include the following methods.
In the case of using the solution polymerization method, a polyvinyl butyral and a solvent are charged into a temperature-adjusting device and a polymerization vessel equipped with a stirrer, and stirred while heating to dissolve the polyvinyl butyral, and then the monomer containing the (meth) acrylic acid is added. For example, a method of polymerizing (meth) acrylic acid by adding a radical polymerization initiator after replacing the air in the polymerization vessel with nitrogen and adding a radical polymerization initiator can be used.
In addition, when using the suspension polymerization method, a polymerization vessel equipped with a temperature controller and a stirrer is charged with a monomer containing polyvinyl butyral, (meth) acrylic acid, pure water, a dispersant, a radical polymerization initiator, For example, a method of polymerizing (meth) acrylic acid by replacing the air with nitrogen and swelling the monomer in polyvinyl butyral and then raising the temperature.
Furthermore, when using the bulk polymerization method, a monomer containing polyvinyl butyral and (meth) acrylic acid is added to a polymerizer equipped with a temperature controller and a stirrer, and stirred while heating to dissolve the polyvinyl butyral in the monomer. Then, after replacing the air in the polymerization vessel with nitrogen, a method of adding a radical polymerization initiator and polymerizing (meth) acrylic acid, and the like can be mentioned.

The radical initiator is not particularly limited. For example, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxyneodecanate, t-butylperoxyneodecanate, t-butylperoxyneoheptanoate, t-hexylperoxypivalate, t-butylperoxypivalate, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1, 3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexano Ate, di (4-methylbenzoyl) peroxide, t-butylperoxy-2-ethylhexanoate , Dibenzoyl peroxide, 1,1-di (t-hexylperoxy) cyclohexane, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylper Organic peroxides such as oxylaurate, t-butyl peroxyisopropyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate, 2,2′-azobisisobutyronitrile, 2,2 ′ -Azo compounds such as azobis (2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis (2-methylbutyronitrile), azobiscyclohexanecarbonitrile, etc. Etc.
These radical initiators may be used alone or in combination of two or more.

Furthermore, the binder resin composition preferably has a structure in which the (meth) acrylic acid resin as a dispersed phase is dispersed in a polyvinyl acetal resin as a continuous phase.
The binder resin composition has a structure composed of a continuous phase and a dispersed phase. After obtaining a film comprising the binder resin composition, the obtained film is used with a razor blade, a microtome, or the like. It can be judged by cutting and observing the cut surface. Examples of the method for observing the cut surface include a method using an optical microscope, a transmission electron microscope, a scanning electron microscope, a phase contrast microscope, a polarizing microscope, a scanning tunnel microscope, a microscopic Raman, a scanning probe microscope, and the like. .

The average dispersed diameter of the (meth) acrylic resin that is the dispersed phase is preferably 0.1 to 10 μm.
The dispersion diameter (diameter) is obtained after obtaining a film made of the binder resin composition, then cutting the obtained film with a razor blade, a microtome, etc., photographing the cut surface, It can be measured by performing analysis processing using an image analyzer. Examples of the method for photographing the cut surface include a method using an optical microscope, a transmission electron microscope, a scanning electron microscope, a phase contrast microscope, a polarizing microscope, a scanning tunnel microscope, a microscopic Raman, and the like. The average dispersed diameter (diameter) can be calculated by obtaining an average value of dispersed diameters (diameters) of 100 arbitrarily selected dispersed phases.
In addition, it is preferable that the said (meth) acrylic-acid type resin is disperse | distributed by the substantially spherical shape in the said polyvinyl acetal type resin as a continuous phase.

By adding inorganic fine particles, a pore former, and an organic solvent to the binder for producing an inorganic sintered body of the present invention, a slurry for producing an inorganic sintered body is obtained. Such a slurry for producing an inorganic sintered body is also one aspect of the present invention.

In the slurry for producing an inorganic sintered body of the present invention, the content of the binder for producing an inorganic sintered body of the present invention is preferably 1 to 200 parts by weight with respect to 100 parts by weight of the inorganic fine particles.
By making the content of the binder 1 part by weight or more, the strength of the obtained green sheet can be increased, and by making it 200 parts by weight or less, cracking and deformation are suppressed in the degreasing firing process. And a porous body having a high porosity can be obtained.

The slurry for producing an inorganic sintered body of the present invention contains inorganic fine particles.
The inorganic fine particles are not particularly limited, and examples thereof include conductive fine particles, magnetic fine particles, ceramic fine particles, and glass fine particles.

The conductive fine particles are not particularly limited as long as they exhibit sufficient conductivity, and examples thereof include powders made of nickel, palladium, platinum, gold, silver, copper, alloys thereof, and the like. These conductive fine particles may be used alone or in combination of two or more.

The magnetic fine particles are not particularly limited. For example, ferrites such as manganese zinc ferrite, nickel zinc ferrite, copper zinc ferrite, barium ferrite and strontium ferrite, metal oxides such as chromium oxide, metal magnetic materials such as cobalt, amorphous Examples include magnetic materials. These magnetic fine particles may be used alone or in combination of two or more.

The ceramic fine particles are not particularly limited. For example, fine particles made of alumina, zirconia, aluminum silicate, titanium oxide, zinc oxide, barium titanate, magnesia, sialon, spinemulite, silicon carbide, silicon nitride, aluminum nitride, or the like. Is mentioned. These ceramic fine particles may be used alone or in combination of two or more.

The glass fine particles are not particularly limited. For example, lead oxide-boron oxide-silicon oxide-calcium oxide glass, zinc oxide-boron oxide-silicon oxide glass, lead oxide-zinc oxide-boron oxide-silicon oxide glass. Etc. These glass fine particles may be used alone or in combination of two or more. Moreover, you may use aluminum oxide etc. together in the range which does not impair the objective of this invention.

The slurry for producing an inorganic sintered body of the present invention contains a pore forming agent.
By containing the pore-forming agent, the slurry for producing the inorganic sintered body is fired and the pore-forming agent is removed, so that the pore-forming agent portion becomes a void and a porous sintered body is produced. Can do. Therefore, it is preferable that the pore forming agent does not dissolve in an organic solvent.

The pore forming agent is not particularly limited as long as it is decomposed and removed by heat. For example, an acrylic resin such as polymethyl methacrylate (PMMA), a polystyrene resin such as polystyrene, a silicon resin, polybutadiene, polyacrylonitrile and Copolymers obtained by polymerizing two or more monomers used for the polymerization of these polymers, such as styrene-butadiene copolymer, butadiene-silicon copolymer, polyvinyl acetal resin, polyvinyl acetate resin, polyvinyl Examples include alcohol resins, cellulose resins such as methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, and carboxyethyl cellulose.

The form of the pore former is not particularly limited, but is preferably granular. In this case, the average particle diameter of the pore former is preferably 0.1 to 100 μm. By making it within the above-mentioned range, the size of the formed void does not become too large, so the strength of the fired body during the degreasing firing is maintained, and cracks and deformation are effectively suppressed in the degreasing firing step. Can do.

In the slurry for producing an inorganic sintered body of the present invention, the content of the pore former is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the inorganic fine particles.
By setting the content of the pore forming agent to 1 part by weight or more, voids can be effectively introduced into the inorganic sintered body after degreasing and firing, and by setting the content to 50 parts by weight or less, voids are formed. Therefore, the strength of the fired body during the degreasing firing is maintained, and cracking and deformation can be effectively suppressed in the degreasing firing process.
Moreover, it is preferable that the said pore making material is 5-40 weight part with respect to 100 weight part of binders.

The slurry for manufacturing an inorganic sintered body of the present invention contains an organic solvent.
The organic solvent is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, butanol, acetone, diethyl ether, tetrahydrofuran, xylene, ethylene glycol and derivatives thereof, butyl carbitol and terpineol. Examples thereof include high boiling point organic solvents and mixed solvents thereof. Among them, when a small amount of an alcohol solvent is used, the viscosity of the binder is lowered, and a paste excellent in handleability can be obtained.
Moreover, rapid drying can be prevented by containing the organic solvent with a boiling point of 80 degreeC or more, and the surface of the green sheet obtained can be smoothed.

The slurry for producing an inorganic sintered body of the present invention may contain a dispersant, a plasticizer, an antioxidant and the like in addition to the above-described inorganic fine particles, binder, pore former and organic solvent.

A ceramic green sheet can be produced by using the binder for producing an inorganic sintered body of the present invention as a binder for molding a ceramic green sheet. Moreover, a fuel cell can be manufactured by using the ceramic green sheet of the present invention.
The method for producing the ceramic green sheet is not particularly limited, and is formed by a known forming method. For example, the binder for producing the inorganic sintered body of the present invention is blended with additives such as a pore-forming agent, a plasticizer, a dispersant, and an antifoaming agent as necessary, and a mixing device such as a ball mill together with an organic solvent and ceramic powder. The slurry may be mixed uniformly to prepare a slurry, and the slurry is wet-coated on a support such as a PET film by a known method such as a doctor blade method, and the organic solvent is removed by drying. In addition, there may be mentioned a method in which the slurry is granulated by a spray dryer method or the like and then the granule is molded by a dry press method.

The ceramic green sheet thus obtained is subjected to various processes such as punching as necessary, and used for manufacturing various ceramic products. For example, when manufacturing a multilayer ceramic capacitor, a conductive paste serving as an internal electrode is applied on a green sheet by screen printing or the like, and then peeled off from a PET film as a support, punched into a predetermined size, and a plurality of sheets It is manufactured by laminating and heat-pressing to produce a laminate, and then thermally decomposing and removing the binder resin by overheating firing.

The method for producing the fuel cell power generation cell is not particularly limited. For example, a plurality of the ceramic green sheets of the present invention are laminated, and the unfired air electrode layer, the unfired solid electrolyte layer, and the unburned fuel electrode layer are integrated. And a method of producing a solid oxide fuel cell power cell stack and firing the resulting stack.

According to the present invention, when it is used as a binder for producing a ceramic green sheet, it has excellent thermal decomposability and can realize a high porosity, and causes defects such as cracks when producing a sintered body. It is possible to provide a binder for producing an inorganic sintered body from which a difficult ceramic green sheet can be obtained. Moreover, the slurry for inorganic sintered compact manufacture using the binder for inorganic sintered compact manufacture, a ceramic green sheet, and a fuel cell power generation cell can be provided.

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

Example 1
(1) Preparation of binder for producing inorganic sintered body In a reaction vessel equipped with a thermometer, a stirrer, a nitrogen introducing tube, and a cooling tube, polyvinyl butyral (degree of polymerization 800, degree of butyralization 68.0 mol%, hydroxyl group amount 31) 0.2 mol%, acetyl group content 0.8 mol%), 25 parts by weight of isobutyl methacrylate, and 100 parts by weight of ethyl acetate were added, and polyvinyl butyral was dissolved while stirring. Next, nitrogen gas was blown for 30 minutes to replace the inside of the reaction vessel with nitrogen, and then the inside of the reaction vessel was heated to 75 ° C. while stirring. After 30 minutes, 0.5 part by weight of t-hexyl peroxypivalate as a polymerization initiator was diluted with 16 parts by weight of ethyl acetate, and the resulting polymerization initiator solution was placed in the reactor over 5 hours. Added dropwise. Thereafter, the mixture was further reacted at 75 ° C. for 3 hours.
Subsequently, the binder for manufacturing an inorganic sintered compact containing the resin composition containing the composite resin comprised by combining polyvinyl butyral and (meth) acrylic acid-type resin was prepared by cooling a reaction liquid.
The weight-average molecular weight of the obtained composite resin was measured using a “2690 Separations Model” manufactured by Waters as a column, and the weight-average molecular weight in terms of polystyrene was measured by the GPC method to be about 270,000. The glass transition temperature of polyisobutyl methacrylate (degree of polymerization 3000) measured using differential scanning calorimetry was 48 ° C.
Using the thermogravimetric analyzer (TGA, manufactured by Hitachi High-Tech Science Co., Ltd., TG / DTA7300), the resin composition thus obtained was heated at a rate of 10% by weight. When measured at 0 ° C./min, the 5 wt% weight loss temperature was 231 ° C. and the 95 wt% weight loss temperature was 516 ° C.

(2) Production of ceramic green sheet The obtained binder for producing an inorganic sintered body was diluted with a diluting solvent (a mixed solvent of ethanol and toluene, and the weight ratio of ethanol and toluene was 1: 1), and the solid content was 10% by weight. A solution was obtained. Next, 20 parts by weight of zirconium oxide powder (TZ-8YS, manufactured by Tosoh Corp.) and 2 parts by weight of a pore-forming agent (methylcellulose powder, average particle size 10 μm) are added as ceramic powder to 20 parts by weight of this solution, and a ball mill is used. And kneaded for 48 hours to obtain a slurry for producing an inorganic sintered body.
Next, the obtained slurry for producing an inorganic sintered body was applied onto a PET film which had been subjected to a release treatment using a coater so that the thickness after drying was 50 μm, air-dried at room temperature for 1 hour, and then hot-air dried. The ceramic green sheet was obtained by drying at 80 ° C. for 3 hours with a machine.

(3) Degreasing and firing the ceramic green sheet The ceramic green sheet thus obtained was heated to 1000 ° C. at a rate of temperature increase of 10 ° C./min in an air atmosphere and held for 2 hours to obtain a ceramic porous sintered body. Obtained.

(Example 2)
In “(1) Preparation of binder for producing inorganic sintered body” in Example 1, 20 parts by weight of isobutyl methacrylate, 3 parts by weight of glycidyl methacrylate, and 2 parts by weight of methacrylic acid were used instead of 25 parts by weight of isobutyl methacrylate. Except for the above, the same operation as in Example 1 was performed to prepare a binder for producing an inorganic sintered body containing a resin composition containing a composite resin.
In addition, when the weight average molecular weight by polystyrene conversion was measured by GPC method using "2690 Separations Model" made from Waters, using the weight average molecular weight of the obtained composite resin as a column, it was about 280,000. Moreover, the glass transition temperature of polyglycidyl methacrylate (degree of polymerization 3000) measured using differential scanning calorimetry was 46 ° C., and the glass transition temperature of polymethacrylic acid was 228 ° C.
The resulting resin composition had a 5 wt% weight loss temperature of 240 ° C and a 95 wt% weight loss temperature of 536 ° C.

Next, a ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Example 3)
In “(1) Preparation of binder for producing inorganic sintered body” in Example 1, instead of 25 parts by weight of isobutyl methacrylate, 20 parts by weight of isobutyl methacrylate, 2 parts by weight of 2-hydroxyethyl methacrylate, and 3 parts by weight of glycidyl methacrylate were added. Except having used, operation similar to Example 1 was performed and the binder for inorganic sintered compact manufacture containing the resin composition containing composite resin was prepared.
In addition, when the weight average molecular weight by polystyrene conversion was measured by GPC method using "2690 Separations Model" made from Waters, using the weight average molecular weight of the obtained composite resin as a column, it was about 300,000. Moreover, the glass transition temperature of poly 2-hydroxyethyl methacrylate (degree of polymerization 3000) measured using differential scanning calorimetry was 55 ° C.
The resulting resin composition had a 5 wt% weight loss temperature of 235 ° C and a 95 wt% weight loss temperature of 533 ° C.

Next, a ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

Example 4
In "(1) Preparation of binder for producing inorganic sintered body" in Example 1, instead of 25 parts by weight of isobutyl methacrylate, 20 parts by weight of 2-ethylhexyl methacrylate, 3 parts by weight of glycidyl methacrylate and 2 parts by weight of methacrylic acid were used. A binder for producing an inorganic sintered body containing a resin composition containing a composite resin was prepared by performing the same operation as in Example 1 except that it was.
The weight-average molecular weight of the obtained composite resin was measured using a “2690 Separations Model” manufactured by Waters as a column, and the weight-average molecular weight in terms of polystyrene was measured by the GPC method to be about 270,000. Moreover, the glass transition temperature of poly 2-ethylhexyl methacrylate (degree of polymerization 3000) measured using differential scanning calorimetry was -10 ° C.
The resulting resin composition had a 5 wt% weight loss temperature of 242 ° C and a 95 wt% weight loss temperature of 516 ° C.

Next, a ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Example 5)
By mixing 20 parts by weight of isobutyl methacrylate, 3 parts by weight of glycidyl methacrylate, 2 parts by weight of methacrylic acid, and 20 parts by weight of ethyl acetate and adding 1 part by weight of t-hexylperoxypivalate, a (meth) acrylic acid resin Was made.
25 parts by weight of polyvinyl butyral (degree of polymerization 800, degree of butyralization 68.0 mol%, hydroxyl amount 31.2 mol%, acetyl group amount 0.8 mol%) and the obtained (meth) acrylic acid resin 25 wt% And a mixture of 1 part by weight (1: 1 by weight) in a mixed solvent of ethanol and toluene (ethanol: toluene = 1: 1) to a solid content of 10% by weight, polyvinyl butyral and (meth) acrylic acid system A binder for producing an inorganic sintered body containing a resin composition containing a resin was produced.
The resulting resin composition had a 5 wt% weight loss temperature of 225 ° C and a 95 wt% weight loss temperature of 511 ° C.

A ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Example 6)
25 parts by weight of polyvinyl butyral partially modified with polyethylene oxide (polymerization degree 800, butyralization degree 67.0 mol%, hydroxyl group amount 25 mol%, acetyl group amount 2 mol%, modified group amount 6 mol%) Was dissolved in a mixed solvent of ethanol and toluene (ethanol: toluene = 1: 1) at a solid content of 10% by weight to prepare a binder for producing an inorganic sintered body containing a resin composition containing polyvinyl butyral.
Moreover, the 5 weight% weight loss temperature of the obtained resin composition was 293 degreeC, and the 95 weight% weight loss temperature was 531 degreeC.

A ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Comparative Example 1)
25 parts by weight of polyvinyl butyral (polymerization degree 800, butyralization degree 68.0 mol%, hydroxyl group amount 31.2 mol%, acetyl group amount 0.8 mol%) was mixed with ethanol and toluene (ethanol: toluene = 1: In 1), a binder for producing an inorganic sintered body containing a resin composition containing polyvinyl butyral dissolved in a solid content of 10% by weight was prepared.
In addition, about polyvinyl butyral, it was 230,000 when the weight average molecular weight by polystyrene conversion was measured by GPC method using "2690 Separations Model" made from Waters as a column.
Moreover, the 5 weight% weight loss temperature of the obtained resin composition was 320 degreeC, and the 95 weight% weight loss temperature was 539 degreeC.

A ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Comparative Example 2)
By mixing 20 parts by weight of isobutyl methacrylate, 3 parts by weight of glycidyl methacrylate, 2 parts by weight of methacrylic acid, and 20 parts by weight of ethyl acetate and adding 1 part by weight of t-hexylperoxypivalate, a (meth) acrylic acid resin Was made.
A resin composition containing 25 parts by weight of the obtained (meth) acrylic acid resin in a mixed solvent of ethanol and toluene (ethanol: toluene = 1: 1) at a solid content of 10% by weight and containing a (meth) acrylic acid resin. A binder for producing an inorganic sintered body containing a product was prepared.
In addition, about the obtained (meth) acrylic acid-type resin, when using the "2690 Separations Model" made from Waters as a column, when the weight average molecular weight by polystyrene conversion was measured by GPC method, it was about 650,000.
Moreover, the 5 weight% weight loss temperature of the obtained resin composition was 240 degreeC, and the 95 weight% weight loss temperature was 322 degreeC.

A ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Comparative Example 3)
In “(1) Preparation of binder for producing inorganic sintered body” in Example 1, the same operation as in Example 1 was carried out except that 25 parts by weight of isobornyl acrylate was used instead of 25 parts by weight of isobutyl methacrylate. The binder for inorganic sintered compact manufacture containing the resin composition containing composite resin was prepared.
In addition, when the weight average molecular weight by polystyrene conversion was measured by GPC method using "2690 Separations Model" made from Waters, using the weight average molecular weight of the obtained composite resin as a column, it was about 260,000.
Further, the resin composition obtained had a 5 wt% weight loss temperature of 311 ° C and a 95 wt% weight loss temperature of 537 ° C.

A ceramic green sheet and a ceramic porous sintered body were obtained in the same manner as in Example 1 except that the obtained binder for producing an inorganic sintered body was used.

(Evaluation method)
The performances of the binder for producing an inorganic sintered body and the ceramic green sheet obtained above were evaluated by the following methods. The results are shown in Table 1.

(Strength / Peelability evaluation)
The obtained ceramic green sheet was peeled from the polyester film, the state of the ceramic green sheet was visually observed, and the strength and peelability were evaluated according to the following criteria.
A: The ceramic green sheet could be peeled cleanly from the polyester film, and no breaks or tears were observed on the peeled sheet.
○: The ceramic green sheet could be peeled cleanly from the polyester film, and small cuts were observed on a small part of the peeled sheet.
X: The ceramic green sheet could not be peeled from the polyester film, or cuts and tears were observed on most of the peeled sheet.

(Adhesiveness)
The obtained green sheet was cut into 10 cm square, and three sheets were stacked and laminated under the thermocompression bonding conditions of a temperature of 80 ° C., a pressure of 180 kg / cm ² , and a time of 5 minutes. The adhesion between the layers was visually observed, and the adhesion was evaluated according to the following criteria.
A: No delamination was observed at all, and the film was firmly bonded.
○: Partial delamination was observed.
X: A considerable amount of delamination was observed.

(Flexibility)
The center part of the green sheet was pressed with a glass core rod having a diameter of 2 mm, a 180 ° bending test was performed around this, and the flexibility was evaluated according to the following criteria.
(Double-circle): The crack was not recognized at all.
◯: Some cracks were observed.
X: Quite many cracks were recognized.

(Sheet stability)
After leaving the obtained green sheet for 10 days, the above strength / peelability evaluation and flexibility were evaluated, and stability was evaluated according to the following criteria.
A: Evaluation results were A or B for strength, peelability and flexibility.
○: The evaluation result of any one of strength, peelability and flexibility was x.
X: Evaluation results were x for strength, peelability and flexibility.

(Sheet peelability)
The obtained green sheets were cut into 10 cm squares, three were stacked, degreased and fired at 400 ° C. in an air atmosphere, visually observed for the presence or absence of delamination, and evaluated according to the following criteria.
A: No delamination was observed.
◯: Some delamination was observed.
X: A considerable amount of delamination was observed.

(crack)
The obtained green sheet was cut into 10 cm square and fired at 1000 ° C. for 1 hour, and the presence or absence of cracks in the ceramic porous sintered body was visually observed and evaluated according to the following criteria.
(Double-circle): The crack was not recognized at all.
◯: Some cracks were observed.
X: Quite many cracks were recognized.

According to the present invention, when it is used as a binder for producing a ceramic green sheet, it has excellent thermal decomposability and can realize a high porosity, and causes defects such as cracks when producing a sintered body. It is possible to provide a binder for producing an inorganic sintered body from which a difficult ceramic green sheet can be obtained. Moreover, the slurry for inorganic sintered compact manufacture using the binder for inorganic sintered compact manufacture, a ceramic green sheet, and a fuel cell power generation cell can be provided.

Claims (10)

For producing an inorganic sintered body, comprising a binder resin composition having a difference between a 5 wt% weight loss temperature and a 95 wt% weight loss temperature of 230 ° C. or more when the temperature is raised at 10 ° C./min binder. 2. The binder for producing an inorganic sintered body according to claim 1, wherein the binder resin composition contains a polyvinyl acetal resin. The binder for producing an inorganic sintered body according to claim 2, wherein the binder resin composition further contains a (meth) acrylic acid resin. 4. The binder for producing an inorganic sintered body according to claim 1, wherein the binder resin composition contains a composite resin composed of polyvinyl butyral and poly (meth) acrylic acid bonded to each other. 5. The binder for producing an inorganic sintered body according to claim 4, wherein the content ratio of polyvinyl butyral in the composite resin is 10 to 90 wt% and the content ratio of poly (meth) acrylic acid is 10 to 90 wt%. The binder for producing an inorganic sintered body according to claim 4 or 5, wherein the (meth) acrylic acid constituting the poly (meth) acrylic acid contains 90% by weight or more of methacrylic acid. The (meth) acrylic acid constituting the poly (meth) acrylic acid contains 3 to 50% by weight of (meth) acrylic acid having a carboxyl group, a hydroxyl group, an epoxy group or an ether group in the molecule. Item 7. A binder for producing an inorganic sintered body according to item 5, 5 or 6. A slurry for producing an inorganic sintered body comprising the binder for producing an inorganic sintered body according to claim 1, 2, 3, 4, 5, 6 or 7, inorganic fine particles, a pore former and an organic solvent. A ceramic green sheet comprising the slurry for producing an inorganic sintered body according to claim 8. A fuel cell power generation cell comprising the ceramic green sheet according to claim 9.