JP2010235689A - Binder resin for inorganic fine particle dispersion, inorganic fine particle dispersion paste composition, and inorganic fine particle dispersion sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder resin for inorganic fine particles dispersion, which is excellent in dispersibility of the inorganic fine particles when used for an inorganic fine particle dispersion paste composition, leaves few carbon after sintering, can be subjected to degreasing treatment even under a low-temperature atmosphere, and can give a sheet having high mechanical strength; and to provide an inorganic fine particle paste composition and inorganic fine particle dispersion sheet. <P>SOLUTION: The binder resin for inorganic fine particle dispersion is used for an inorganic fine particle dispersion sheet has a segment derived from methacrylate having a 1-4C aliphatic hydrocarbon group in its ester part and a segment derived from polyethylene glycol monomethacrylate, and contains 30-50 wt.% of the segment derived from polyethylene glycol monomethacrylate. Moreover, The repeating number of ethylene oxide in the polyethylene glycol monomethacrylate is 20-50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention is excellent in dispersibility of inorganic fine particles when used in an inorganic fine particle-dispersed paste composition, has little residual carbon after sintering, can be degreased even in a low temperature atmosphere, and mechanically The present invention relates to a binder resin for dispersing inorganic fine particles, an inorganic fine particle-dispersed paste composition, and an inorganic fine particle-dispersed sheet capable of obtaining a sheet having high strength.

In recent years, inorganic fine particle-dispersed paste compositions in which inorganic fine particles such as conductive powder, ceramic powder, glass particles and the like are dispersed in a binder resin, and inorganic fine particle-dispersed sheets obtained by using them obtain fired bodies of various shapes. It is used for. For example, a paste composition in which metal fine particles are dispersed as a conductive powder is used for circuit formation, capacitor production, and the like, and a glass paste in which glass particles are dispersed is used for a dielectric of a plasma display panel (hereinafter also referred to as PDP). A ceramic powder-dispersed sheet used for manufacturing a body layer and a rib layer and obtained by forming a ceramic paste in which a ceramic powder is dispersed is used for manufacturing a multilayer ceramic capacitor.

A multilayer electronic component such as a multilayer ceramic capacitor is generally manufactured through the following steps as disclosed in Patent Document 1, for example.
First, after adding a plasticizer, a dispersing agent, etc. to the solution which melt | dissolved binder resin in the organic solvent, ceramic raw material powder is added. Next, it is uniformly mixed by a ball mill or the like and defoamed to obtain a ceramic slurry composition having a constant viscosity. The obtained ceramic slurry composition is cast-molded on a support surface such as a polyethylene terephthalate film or a stainless steel plate which has been subjected to mold release treatment using a doctor blade, a reverse roll coater or the like. Next, volatile components such as an organic solvent are distilled off by heating or the like, and then peeled off from the support to obtain a ceramic green sheet.

On the obtained ceramic green sheet, a plurality of conductive pastes applied as internal electrodes applied by screen printing or the like are alternately stacked and thermocompression bonded to produce a laminate. Forming external electrodes on the end face of the fired ceramic product after pyrolyzing and removing the binder resin component contained in the laminate (so-called “degreasing”) Through the process, a multilayer ceramic capacitor is obtained.

As described above, in the method for manufacturing a multilayer ceramic capacitor, the inorganic fine particle dispersed paste composition is directly printed on a substrate and the various inorganic powders are sequentially sintered as in the manufacturing method such as PDP. After each ceramic green sheet is manufactured in step 2, the ceramic green sheet is laminated and sintered in the final process. Therefore, the binder resin used requires sheet strength and flexibility in addition to performance such as viscosity. Depending on the product, punchability is also required. In particular, such performance is strongly required for green sheets used in multilayer capacitors, multilayer piezoelectric elements, multilayer inductors, multilayer substrates, multilayer heat exchangers, and the like.

In recent years, electronic parts such as multilayer ceramic capacitors have been strongly demanded to be lighter, smaller and cheaper. Accordingly, in the ceramic laminate required for manufacturing these, it is possible to reduce the sheet thickness per layer or to further increase the number of layers. On the other hand, expensive Pt is required for forming the internal electrode. An inexpensive base metal material replacing Pd, Ag, or the like, for example, a conductive paste containing Ni or Cu having excellent high frequency characteristics as a main component is used.

When an electrode layer is formed using a conductive paste mainly composed of such a base metal material, it is necessary to perform a debinding process and a baking process for the multilayer body in a non-oxidizing atmosphere during the manufacturing process. However, particularly when the conductive paste is mainly composed of Cu, heating at a high temperature in an oxygen-containing atmosphere results in the formation of a high-quality insulator oxide. Therefore, it is necessary to lower the baking temperature.
However, when firing in a non-oxidizing atmosphere, the binder in the green sheet remains as carbon, and pores (pores) generated due to the presence of carbon remain in the fired body. For this reason, there has been a problem in characteristics of the electronic component after manufacture.

Then, using the acrylic resin excellent in low temperature decomposability as a binder is examined. That is, the acrylic resin can undergo depolymerization (chemical reaction in which the polymer is decomposed into monomers) even at low temperatures, so that the carbon residual ratio (hereinafter referred to as the residual carbon ratio) in the green sheet can be reduced. This is because it is considered possible. For example, Patent Document 2 discloses a method using an acrylic resin having a very low high-temperature residual weight.
However, the acrylic resin has poor dispersibility of the raw material powder, and the homogeneity of the green sheet has been impaired. In addition, as the homogeneity deteriorated, the physical properties such as the sheet strength, sheet elongation, sheet molding density, and sheet punching property of the green sheet decreased.

On the other hand, Patent Document 3 and Patent Document 4 use a methacryl monomer having a short-chain polyalkylene ether in the side chain as a binder resin, thereby improving the polarity of the binder resin while improving the sinterability. , Has improved affinity with metals.
However, in these techniques, polyalkylene ether is used to express the effect of increasing the polarity of the binder, but the resulting green sheet is still inferior in mechanical strength.

Japanese Patent Publication No. 3-35762 JP 2001-307548 A Japanese Patent No. 3355694 JP-A-6-072759

In view of the above situation, the present invention is excellent in dispersibility of inorganic fine particles when used in an inorganic fine particle dispersed paste composition, and can be degreased even in a low temperature atmosphere with little residual carbon after sintering. And it aims at providing the binder resin for inorganic fine particle dispersion | distribution which can obtain a sheet | seat with high mechanical strength. Another object of the present invention is to provide an inorganic fine particle dispersed paste composition and an inorganic fine particle dispersed sheet using the inorganic fine particle dispersing binder resin.

The present invention relates to a binder resin for dispersing inorganic fine particles used for inorganic fine particle dispersed sheets, a segment derived from a methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in an ester portion, and polyethylene glycol monomethacrylate. Inorganic fine particle dispersion having a segment derived from polyethylene glycol monomethacrylate, the content of the segment derived from polyethylene glycol monomethacrylate being 30 to 50% by weight, and the polyethylene glycol monomethacrylate having a repeating number of ethylene oxide of 20 to 50 It is a binder resin.
The present invention is described in detail below.

As a result of intensive studies, the present inventors have found that a polyethylene glycol monomethacrylate that causes deterioration of thermal decomposability has a predetermined ratio of methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion. It has been found that when the copolymerized polymer is used as a binder resin for dispersing inorganic fine particles, the dispersibility of the inorganic fine particles can be sufficiently secured while minimizing the deterioration of thermal decomposability. Further, it has been found that when such a binder resin for dispersing inorganic fine particles is used, generation of soot during combustion is suppressed, and residual carbon after sintering can be reduced.
However, a molded body obtained using such a binder resin for dispersing inorganic fine particles exhibits brittle physical properties, and a new problem has arisen that it is difficult to use it for an inorganic fine particle dispersed sheet having a thickness of 20 μm or more.
On the other hand, as a result of further intensive studies, the inventors of the present invention can obtain a polyethylene glycol monomethacrylate having an ethylene oxide repeat number of 20 to 50 while having sufficient dispersibility and thermal decomposability. It has been found that the elongation characteristics and workability of the molded product are greatly improved, and the present invention has been completed.

The binder resin for dispersing inorganic fine particles of the present invention has a segment derived from a methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion, and a segment derived from polyethylene glycol monomethacrylate. By having the above two types of segments and the content of the segment derived from polyethylene glycol methacrylate and the number of repetitions thereof as a predetermined amount, for example, when used as a binder resin of a ceramic green sheet, it is obtained. The resulting ceramic green sheet has good elongation characteristics, can achieve degreasing at low temperatures, and can reduce residual carbon after sintering. Such an improvement tendency is particularly noticeable in a sheet having a thickness of 20 μm or more, which requires high flexibility and strength.
In the present specification, low temperature degreasing is 99.5% by weight or more of the initial weight of the binder resin for dispersing inorganic fine particles when held at 400 ° C. for 1 hour in a normal air atmosphere in which nitrogen substitution or the like is not performed. Means to be decomposed.

The binder resin for dispersing inorganic fine particles of the present invention contains a segment derived from methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion.
Examples of the methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion include methyl methacrylate, butyl methacrylate, and isobutyl methacrylate. These methacrylates have the characteristics that they are excellent in thermal decomposability when made into a homopolymer and have little residual carbon content.

These methacrylates may be used alone or in combination of two or more.
When using 2 or more types together, the workability | operativity of an inorganic fine particle dispersion | distribution sheet is influenced by the combination of the methacrylate to be used. Specifically, when the amount of methyl methacrylate increases, the sheet becomes hard, and when the amount of butyl methacrylate decreases, the sheet becomes soft. Therefore, in order to improve workability, it is preferable to use a combination of methacrylates within an appropriate range.

The minimum with preferable content of the segment originating in the methacrylate which has a C1-C4 aliphatic hydrocarbon group in the said ester part is 60 weight%, and a preferable upper limit is 70 weight%. When the content of the methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion is less than 60% by weight, the adverse effect of polyethylene glycol monomethacrylate on the thermal decomposability cannot be ignored, and the residue after firing Since the amount of carbon increases, the decomposition end temperature may also increase. When the content of the methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester part exceeds 70% by weight, the strength of the inorganic fine particle dispersed sheet cannot be maintained by reducing the content of polyethylene glycol monomethacrylate, Workability will be greatly impaired.

The binder resin for dispersing inorganic fine particles of the present invention has a segment derived from polyethylene glycol monomethacrylate. Since the segment derived from the polyethylene glycol monomethacrylate has a crystalline structure, the ethylene oxide segment forms a eutectic with a polyethylene glycol chain extending from another molecular chain to form a pseudo-crosslinking point. Therefore, properties similar to rubber can be obtained, and the elongation characteristics can be greatly improved.

As said polyethyleneglycol monomethacrylate, what has a hydroxyl group, a methoxy group, an ethoxy group, a lauryloxy group, a phenoxy group etc. can be used at the molecular terminal. Further, a copolymer of polyethylene glycol such as polyethylene glycol-polypropylene glycol monomethacrylate and other types of polyethers having a high polyethylene glycol composition ratio and exhibiting crystallinity can also be used.
Specific examples of the polyethylene glycol monomethacrylate include methoxypolyethylene glycol monomethacrylate.

The lower limit of the polyethylene glycol monomethacrylate content is 30% by weight, and the upper limit is 50% by weight. When the content of the polyethylene glycol monomethacrylate is less than 30% by weight, the crystallinity for obtaining a sufficient sheet strength is not expressed, and the workability does not improve because it does not work as a pseudo-crosslinking point. When the content of the polyethylene glycol monomethacrylate exceeds 50% by weight, the degradability is deteriorated and the solubility in the solvent used is lowered. The minimum with preferable content of the said polyethyleneglycol monomethacrylate is 30 weight%, and a preferable upper limit is 40 weight%.

The lower limit of the number of ethylene oxide repeats of the polyethylene glycol monomethacrylate is 20, and the upper limit is 50. When the number of ethylene oxide repeats is less than 20, the crystallinity for obtaining sufficient sheet strength is not expressed, and the workability does not improve because it does not work as a pseudo-crosslinking point. When the repeating number of the ethylene oxide exceeds 50, degradation of degradation or degradation of solubility in the solvent used occurs. Further, at the time of synthesizing the binder resin for dispersing the inorganic fine particles, the coexistence ratio of each homopolymer increases in the copolymer component, so that sufficient strength cannot be imparted even if the crystallinity is confirmed. The preferable lower limit of the number of repeating ethylene oxide is 25, and the preferable upper limit is 35.

In the present invention, the content of the polyethylene glycol monomethacrylate and the number of ethylene oxide repeats must be simultaneously within a predetermined range. It is conceivable to give strength by using a small amount of polyethylene glycol monomethacrylate with a large number of ethylene oxide repeats, but in that case, the number of pseudo-crosslinking points will be reduced, and sufficient strength cannot be imparted, and brittleness will appear strongly. As a result, workability becomes very bad.

The binder resin for dispersing inorganic fine particles of the present invention preferably has at least one hydrogen bonding functional group at the molecular end. The presence of the hydrogen-bonding functional group only at the molecular end allows the inorganic fine particle-dispersed paste composition to be appropriate even if it is not incorporated in a large amount without impairing the effects of the present invention such as low-temperature thermal decomposability. A high viscosity can be secured.

The hydrogen bonding functional group is not particularly limited, and examples thereof include a hydroxyl group, a carboxyl group, and an amino group. Of these, a hydroxyl group and a carboxyl group are preferable because of less influence during thermal decomposition. In addition, it is sufficient that at least one hydrogen-bonding functional group is present, but the greater the number, the better the dispersibility of the inorganic fine particles in the inorganic fine particle-dispersed paste composition.

In the binder resin for dispersing inorganic fine particles of the present invention, the preferred lower limit of the weight average molecular weight in terms of polystyrene is 20,000, and the preferred upper limit is 1,000,000. When the weight average molecular weight is less than 20,000, the strength is lowered, the viscosity is not sufficiently obtained at the time of preparing the paste, the storage stability is deteriorated, and the strength when formed into a sheet is remarkably lowered. When the weight average molecular weight exceeds 1,000,000, there may be a problem in the stringiness and solubility in a solvent of the resulting inorganic fine particle dispersed paste composition.
In addition, the measurement of the weight average molecular weight by polystyrene conversion can be obtained by performing a gel permeation chromatography (GPC) measurement using, for example, a column LF-804 manufactured by SHOKO as a column.

In addition to the segment derived from the methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion, and the segment derived from polyethylene glycol monomethacrylate, the binder resin for dispersing inorganic fine particles of the present invention has a desired In order to add functionality, you may have the segment derived from the methacryl monomer which has a polar group in the range which does not impair the effect of this invention.
Examples of the methacrylic monomer having a polar group include a methacrylate monomer having a polar group and methacrylic acid.

Examples of the methacrylate monomer having a polar group include 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, and glycerol monomethacrylate.

When it has a segment derived from the methacrylic monomer having the polar group, the content of the segment derived from the methacrylic monomer having the polar group is preferably less than 5% by weight. If the content of the segment derived from the methacrylic monomer having a polar group is 5% by weight or more, the thermal decomposition property at low temperature is impaired or the amount of wrinkles adhering to the inorganic fine particles increases, and the residual carbon of the sintered body May increase.

In addition to the segment derived from the methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion, and the segment derived from polyethylene glycol monomethacrylate, the binder resin for dispersing inorganic fine particles of the present invention has a desired In order to add functionality, you may have the segment derived from an acrylate monomer in the range which does not impair the effect of this invention.

Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl methacrylate, acrylic acid, and hydroxyethyl acrylate.

When it has a segment derived from the acrylate monomer, the content of the segment derived from the acrylate monomer is preferably less than 10% by weight. When the content of the segment derived from the acrylate monomer is 10% by weight or more, the thermal decomposability at a low temperature is impaired, or the thermal decomposability of the binder itself is deteriorated and the residual carbon of the sintered body is increased. Sometimes.

The method for producing the binder resin for dispersing inorganic fine particles of the present invention is not particularly limited. For example, a chain having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester part, polyethylene glycol monomethacrylate as a raw material monomer, chain Examples thereof include a method of preparing a monomer mixed solution containing a transfer agent and an organic solvent, and then adding a polymerization initiator to the monomer mixed solution to copolymerize the raw material monomers.

In addition, as a method for introducing a hydrogen bondable functional group only to the molecular terminal of the binder resin for dispersing inorganic fine particles of the present invention, for example, in the above-described ester portion under a chain transfer agent having a hydrogen bondable functional group. Conventional monomers such as a free radical polymerization method, a living radical polymerization method, an iniferter polymerization method, an anionic polymerization method, a living anion polymerization method, etc., for raw material monomers comprising a methacrylate having a C 1-4 aliphatic hydrocarbon group and polyethylene glycol monomethacrylate A copolymerization method by a known method or a monomer having a hydrogen bonding functional group, the above-mentioned monomers can be converted into a free radical polymerization method, a living radical polymerization method, an iniferter polymerization method, an anionic polymerization method, a living anion. The method of copolymerizing by conventionally well-known methods, such as a polymerization method, is mentioned. These methods may be used in combination.
Moreover, it can be confirmed by, for example, ¹³ C-NMR that a hydrogen bonding functional group has been introduced only into the molecular terminals of the binder resin for dispersing inorganic fine particles.

The chain transfer agent having a hydrogen bonding functional group is not particularly limited, and examples thereof include mercaptopropanediol having a hydroxyl group as a hydrogen bonding functional group, thioglycerol having a carboxyl group as a hydrogen bonding functional group, and mercaptosuccinic acid. , Mercaptoacetic acid, aminoethanethiol having an amino group as a hydrogen bonding functional group, and the like.

The polymerization initiator having a hydrogen bonding functional group is not particularly limited. For example, P-menthane hydroperoxide (“Permenta H” manufactured by NOF Corporation), diisopropylbenzene hydroperoxide (“PARK Mill P” manufactured by NOF Corporation) ), 1,2,3,3-tetramethylbutyl hydroperoxide (“Perocta H” manufactured by NOF Corporation), cumene hydroperoxide (“PARK Mill H-80” manufactured by NOF Corporation), t-butyl hydroperoxide (NOF Corporation) “Perbutyl H-69”), cyclohexanone peroxide (“Perhexa H” manufactured by NOF Corporation), 1,1,3,3-tetramethylbutyl hydroperoxide, t-butyl hydroperoxide, t-amyl hydro Peroxide, Disuccinic acid peroxide (Perroyl SA), etc. are mentioned.

Also, an inorganic fine particle dispersed paste composition can be prepared using the binder resin for dispersing fine inorganic particles of the present invention, an organic solvent, and inorganic fine particles.
The inorganic fine particle-dispersed paste composition containing the inorganic fine particle-dispersing binder resin, the organic solvent, and the inorganic fine particles of the present invention is also one aspect of the present invention.

The inorganic fine particle-dispersed paste composition of the present invention contains inorganic fine particles.
The inorganic fine particles are not particularly limited. For example, copper, silver, nickel, palladium, aluminum, alumina, zirconia, titanium oxide, barium titanate, alumina nitride, silicon nitride, boron nitride, silicate glass, lead glass, _{CaO · Al 2 O 3 · SiO} 2 type inorganic _{glass, MgO · Al 2 O 3 ·} SiO 2 type inorganic _{glass, LiO 2 · Al 2 O 3} · SiO 2 type low melting point glass such as inorganic glass, _BaMgAl 10 _{O 17:} Examples include phosphors such as Eu, Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Eu, various carbon blacks, carbon nanotubes, metal complexes, and the like.

The content of the inorganic fine particles in the inorganic fine particle-dispersed paste composition of the present invention is not particularly limited, but a preferred lower limit is 10% by weight and a preferred upper limit is 90% by weight. If the amount is less than 10% by weight, the viscosity may not be sufficiently obtained or the coatability may be lowered. If the amount exceeds 90% by weight, it may be difficult to disperse the inorganic fine particles.

The inorganic fine particle dispersed paste composition of the present invention contains an organic solvent.
The organic solvent is not particularly limited, for example, toluene, ethyl acetate, butyl acetate, isopropanol, methyl isobutyl ketone, methyl ethyl ketone, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, Diethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, trimethylpentanediol monoisobutyrate, butyl carbitol, butyl carbitol acetate, terpineol, terpineol acetate, dihydroterpineol, dihydroterpineol acetate texanol, isophorone, butyl lactate, dioctyl phthalate, dioctyl adipate , Benji Alcohol, phenyl propylene glycol, cresol, and the like. Among them, terpineol acetate, dihydroterpineol acetate, dihydroterpineol acetate, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, butyl carbitol, butyl carbitol acetate, and texanol are preferable, and terpineol, terpineol acetate, dihydroterpineol, dihydroterpineol. Acetate is more preferred. In addition, these organic solvents may be used independently and may use 2 or more types together.

The content of the binder resin for dispersing inorganic fine particles in the inorganic fine particle dispersed paste composition of the present invention is not particularly limited, but a preferred lower limit is 5% by weight and a preferred upper limit is 30% by weight. When the content of the binder resin for dispersing inorganic fine particles is within the above range, an inorganic fine particle-dispersed paste composition that can be degreased even when fired at a low temperature can be produced.

Although it does not specifically limit as content of the said organic solvent in the inorganic fine particle dispersion paste composition of this invention, A preferable minimum is 5 weight% and a preferable upper limit is 60 weight%. If it is out of this range, the coatability may be lowered or it may be difficult to disperse the inorganic fine particles.

The inorganic fine particle dispersed paste composition of the present invention may contain an adhesion promoter.
The adhesion promoter is not particularly limited, but an aminosilane-based silane coupling agent is preferably used.
Examples of the aminosilane-based silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (amino Ethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl -3-aminopropyltrimethoxysilane.
Besides aminosilane silane coupling agents, glycidylsilane silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, In addition, dimethyldimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and the like, which are silane coupling agents, can be suitably used, and a plurality of these may be used.

The inorganic fine particle-dispersed paste composition of the present invention preferably contains a nonionic surfactant for the purpose of promoting leveling after coating.
The nonionic surfactant is not particularly limited, but is preferably a nonionic surfactant having an HLB value of 10 or more and 20 or less. Here, the HLB value is used as an index representing the hydrophilicity and lipophilicity of a surfactant, and several calculation methods have been proposed. For example, saponification value of an ester-based surfactant And S, the acid value of the fatty acid constituting the surfactant is A, and the HLB value is 20 (1-S / A). Specifically, a nonionic surfactant having a polyethylene oxide in which an alkylene ether is added to an aliphatic chain is preferable. Specifically, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and the like are preferably used. It is done. The nonionic surfactant has good thermal decomposability, but if added in a large amount, the thermal decomposability of the inorganic fine particle-dispersed paste composition may be lowered. Therefore, the preferable upper limit of the content is 5% by weight. .

Further, the inorganic fine particle dispersed paste composition of the present invention may further contain, as additives, a plasticizer, a tackifier, a storage stabilizer, an antifoaming agent, a thermal decomposition accelerator, an antioxidant and the like. These additives are not particularly limited, and those commonly used in this field can be appropriately selected.

The method for producing the inorganic fine particle-dispersed paste composition of the present invention is not particularly limited, and includes conventionally known methods, such as a method of mixing each component using various mixers such as a ball mill, a blender mill, and a three roll. Is mentioned.

The inorganic fine particle dispersed paste composition of the present invention can be suitably used as a glass paste composition when a glass powder is used as the inorganic fine particles, and a glass fine particle dispersed sheet can be obtained. Further, when ceramic powder is used as the inorganic fine particles, it can be suitably used as a ceramic sheet composition, and when aluminum powder is used as the inorganic fine particles, it can be suitably used as an aluminum sheet composition.

The binder resin for dispersing inorganic fine particles of the present invention can be suitably used as a material for a green sheet having a thickness of several tens of μm by using glass powder or ceramic powder as inorganic fine particles. By using the inorganic fine particle dispersed paste composition of the present invention for these applications, degreasing at a low temperature is possible, and oxidation during sintering of the inorganic fine particles during sintering can be suppressed to a minimum.

When the inorganic fine particle-dispersed paste composition of the present invention is used as a green sheet material, the organic solvent used is particularly preferably toluene, ethyl acetate, butyl acetate, isopropanol, methyl isobutyl ketone, methyl ethyl ketone, or the like. Moreover, it is desirable that the amount of the organic solvent added is appropriately selected depending on the coating process to be used, and is not particularly limited. Further, when the inorganic fine particle-dispersed paste composition of the present invention is used as a green sheet material, the content of the inorganic fine particles is not particularly limited, but a preferred lower limit is 50% by weight and a preferred upper limit is 95% by weight. When the content of the inorganic fine particles is less than 50% by weight, the binder resin component increases and the sinterability may decrease. When the content exceeds 95% by weight, it becomes difficult to disperse the inorganic fine particles, It may not be possible to make a sheet.

The inorganic fine particle-dispersed paste composition of the present invention is coated on a support film that has been subjected to a single-sided release treatment, the solvent is dried, and the sheet is formed into a sheet, thereby producing an inorganic fine particle-dispersed sheet such as a green sheet. be able to. Such an inorganic fine particle dispersed sheet is also one aspect of the present invention.
As a method for producing the inorganic fine particle-dispersed sheet of the present invention, for example, the binder resin for dispersing inorganic fine particles of the present invention is dissolved in a solvent, a surfactant, a dispersant, a plasticizer, etc. are added, and a uniform vehicle is stirred. After the preparation, inorganic fine particles are added and uniformly dispersed using a ball mill dispersing device. Examples thereof include a method of uniformly forming a coating film on a support film by applying the obtained inorganic fine particle dispersed paste composition by a coating method such as a roll coater, a die coater, a squeeze coater, or a curtain coater.

The support film used when producing the inorganic fine particle-dispersed sheet sheet of the present invention is preferably a resin film having heat resistance and solvent resistance and flexibility. Since the support film has flexibility, the paste composition for forming the inorganic fine particle dispersion sheet can be applied to the surface of the support film by a roll coater, a blade coater or the like, and the resulting inorganic fine particle dispersion sheet forming film is rolled. Can be stored and supplied in a wound state.

Examples of the resin that forms the support film include polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyimide, polyvinyl alcohol, polyvinyl chloride, polyfluoroethylene, and other fluorine-containing resins, nylon, and cellulose.
As for the thickness of the said support film, 20-100 micrometers is preferable, for example.
Moreover, it is preferable that the surface of the support film is subjected to a mold release treatment, whereby the support film can be easily peeled off in the transfer step.

According to the present invention, when used in an inorganic fine particle-dispersed paste composition, the inorganic fine particles are excellent in dispersibility, can be degreased even in a low-temperature atmosphere with little residual carbon after sintering, and It is possible to provide a binder resin for dispersing inorganic fine particles capable of obtaining a sheet having high mechanical strength. In addition, according to the present invention, an inorganic fine particle dispersed paste composition and an inorganic fine particle dispersed sheet using the binder resin for dispersing inorganic fine particles can be provided.

It is a differential scanning calorimetry data of Examples 1 to 3 and Comparative Example 1. 5 is differential scanning calorimetry data of Examples 4 to 5 and Comparative Example 2. It is a differential scanning calorimetry data of Examples 3 and 5 and Comparative Example 4.

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

Example 1
(1) Preparation of binder resin, inorganic fine particle-dispersed paste composition In a 2 L separable flask equipped with a stirrer, cooler, thermometer, hot water bath and nitrogen gas inlet, isobutyl methacrylate (IBMA) 70 parts by weight, methoxypolyethylene 30 parts by weight of glycol monomethacrylate (MPEGMA, manufactured by Kyoeisha Chemical Co., Ltd., light ester 041MA, ethylene oxide repeat number 30), thioglycol (Blenmer TGL manufactured by NOF Corporation) as a chain transfer agent, and 100 parts by weight of butyl acetate as an organic solvent Mixing was performed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system was replaced with nitrogen gas and heated until the hot water bath boiled with stirring. A solution obtained by diluting the polymerization initiator with butyl acetate was added. Further, a butyl acetate solution containing a polymerization initiator was added several times during the polymerization.

Seven hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. This obtained the butyl acetate solution of the (meth) acrylic resin. The obtained polymer was analyzed by gel permeation chromatography using a column LF-804 manufactured by SHOKO as a column, and the weight average molecular weight in terms of polystyrene was as shown in Table 1.
70 parts by weight of alumina (average particle size 2.0 μm) as inorganic powder is added to 30 parts by weight of the butyl acetate solution of the (meth) acrylic resin thus obtained, and kneaded with a high-speed stirrer to disperse the inorganic fine particles. A paste composition was obtained.

(2) Production of Green Sheet Using a blade coater on a support film (width 400 mm, length 30 m, thickness 38 μm) made of polyethylene terephthalate (PET), which was previously subjected to release treatment, from the obtained inorganic fine particle dispersed paste composition The coating film thus formed was dried at 100 ° C. for 10 minutes to remove the solvent, thereby forming an inorganic powder-containing resin layer having a thickness of 100 μm on the support film to produce a green sheet. In the following examples, the amount of solvent was adjusted to unify the thickness.

(Example 2)
An inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that the addition amount of isobutyl methacrylate was 65 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 35 parts by weight.

Example 3
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that the addition amount of isobutyl methacrylate was 60 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 40 parts by weight.

Example 4
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that MPEGMA having an ethylene oxide repetition number of 23 (Blenmer PMG1000) was used as methoxypolyethylene glycol monomethacrylate.

(Example 5)
An inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 4 except that the addition amount of isobutyl methacrylate was 60 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 40 parts by weight.

(Example 6)
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 1, except that MPEGMA having an ethylene oxide repetition number of 46 (Blenmer PMG2000) was used as methoxypolyethylene glycol monomethacrylate.

(Example 7)
An inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that n-butyl methacrylate was used instead of isobutyl methacrylate.

(Example 8)
An inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that methyl methacrylate was used in place of isobutyl methacrylate.

Example 9
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that 50 parts by weight of isobutyl methacrylate was added and 20 parts by weight of methyl methacrylate was added.

(Example 10)
As in Example 8, except that polyoxyethylene alkyl ether (manufactured by Nippon Surfactant Co., Ltd., product name NIKOL BL25) was added as a nonionic surfactant so as to be 1% by weight with respect to the resin component in the sheet. To get a green sheet.

(Comparative Example 1)
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that the addition amount of isobutyl methacrylate was 75 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 25 parts by weight.

(Comparative Example 2)
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 4 except that the addition amount of isobutyl methacrylate was 75 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 25 parts by weight.

(Comparative Example 3)
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 6 except that the addition amount of isobutyl methacrylate was 75 parts by weight and the addition amount of methoxypolyethylene glycol monomethacrylate was 25 parts by weight.

(Comparative Example 4)
An inorganic fine particle-dispersed paste composition and a green sheet were obtained in the same manner as in Example 3 except that MPEGMA having 9 ethylene oxide repeats (Kyoeisha Chemical Co., Ltd., light ester 130MA) was used as methoxypolyethylene glycol monomethacrylate.

(Comparative Example 5)
The synthesis of the polymer was attempted in the same manner as in Example 1 except that the addition amount of methoxypolyethylene glycol monomethacrylate was 60 parts by weight and the addition amount of isobutyl methacrylate was 40 parts by weight. Although the obtained polymerization solution was cloudy, an inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1.

(Comparative Example 6)
The synthesis of the polymer was attempted in the same manner as in Example 1 except that MPEGMA having a repeating number of ethylene oxide of 90 (manufactured by NOF Corporation, Blenmer PMG4000) was used as methoxypolyethylene glycol monomethacrylate. Although the obtained polymerization solution was cloudy, an inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1.

(Comparative Example 7)
An inorganic fine particle dispersed paste composition and a green sheet were obtained in the same manner as in Example 1 except that 2-ethylhexyl methacrylate was used instead of isobutyl methacrylate.

(Comparative Example 8)
In Example 10, polyoxyethylene alkyl ether (manufactured by Nippon Surfactant Kogyo Co., Ltd .: product name NIKOL BL25) as a nonionic surfactant for the polymer obtained only with methyl methacrylate without using methoxypolyethylene glycol monomethacrylate. Was added in the same manner as in Example 10 except that 1% by weight was added to the resin component in the sheet.

<Evaluation>
The following evaluation was performed about the binder resin, the inorganic fine particle dispersion paste composition, and the green sheet obtained in Examples 1 to 10 and Comparative Examples 1 to 8. The results are shown in Table 1.

(1) Punching property The punching test of the obtained green sheet was performed using eyelet removal with a diameter of 1 cm. Specifically, the determination was made based on whether or not the punched circular portion and the punched sheet side were punched without cracks or chipping. The ones that were beautifully broken out of all five times were marked with ◎, the ones with cracks and chips in one of the five times were marked with ○, the ones with all cracks and chips marked with ×, and the others were marked with △.

(2) Sinterability The green sheets produced in Examples and Comparative Examples were transferred to a glass substrate, heated to 400 ° C. at 10 ° C./min in a muffle furnace purged with nitrogen, and then in a state of 400 ° C. Hold for 1 hour to finish the sintering. The green sheet was taken out of the muffle furnace and visually checked for baked color. The uncolored ones were evaluated as ◎, the pale yellow one as ◯, and the brown one as ×.

(3) Windability test A green sheet produced in Examples and Comparative Examples was bonded to a protective film as a PET film having a mold release treatment on one side to produce a glass sheet.
The obtained glass sheet was wound around a polypropylene pipe having a diameter of 20 cm and a length of 50 cm, and was cured in a roll state at a room temperature of 23 ° C. for 24 hours.
A portion of 5 m or 10 m was cut from the roll end, and it was visually confirmed whether or not a defect such as a crack occurred in the green sheet. Those that could not be wound were rated as xx, those that had cracks were marked as x, and those that did not crack were marked as ◯.

(4) Thermal analysis The polymer obtained in Examples 1 to 5 and Comparative Examples 1 to 2 and 4 was subjected to differential scanning thermal analysis using DSC6200 (manufactured by Seiko Instruments Inc.).
The results are shown in FIGS. 1 shows the results of Examples 1 to 3 and Comparative Example 1, FIG. 2 shows the results of Examples 4 to 5 and Comparative Example 2, and FIG. 3 shows Examples 3 and 5 and Comparative Example 4. The result was shown. FIG. 1 is a comparison of cases in which the content of the ethylene oxide repeating number of 30 is changed using MPEGMA. FIG. 2 compares the case where the content was changed using MPEGMA having an ethylene oxide repeating number of 23. Further, FIG. 3 compares the case where 40 parts by weight of MPEGMA is added and the number of ethylene oxide repetitions is changed.

As shown in Table 1, good results were obtained for both the binder resin and the green sheet obtained in the examples. When Examples and Comparative Examples are compared, when the amount of MPEGMA added is less than 30 parts by weight, or when the number of ethylene oxide repeats of MPEGMA is 20 or less, there is a problem in punchability and winding properties. I understand that.
Such results are also correlated with the results of differential scanning calorimetry shown in FIGS. That is, in the examples, endothermic data that can be determined as the heat of fusion of crystals was obtained, but in the comparative examples inferior in punchability and strength, none of the endothermic data considered to be derived from the crystal part was obtained. Therefore, the polymer obtained in the example has a portion crystallized when it is made into a sheet, and it is specific compared to the case where it does not have crystallinity because it becomes a pseudo-crosslinking point. It is considered to indicate strength.

Further, from the results of Comparative Examples 5 to 6, it can be seen that when the amount of MPEGMA added and the number of repetitions are increased, a problem arises in the sinterability even if the punching property and winding property are good. This is considered to be caused by a high ratio of ethylene oxide sites in the green sheet.
In Comparative Example 7, the green sheet was evaluated when a polymer having a long fatty chain in the side chain was used, but there was a problem in the sinterability as well.

Furthermore, from the results of Examples 7 to 9, it can be seen that good results are obtained even when not only isobutyl methacrylate but also butyl methacrylate or methyl methacrylate is used as the methacrylate having an aliphatic hydrocarbon group. In the green sheet obtained in Example 8, the punchability was slightly deteriorated because the balance with the hard and brittle characteristics peculiar to methyl methacrylate was performed in a slightly brittle direction while having the effect of crystallinity. This point can be improved by copolymerizing more flexible isobutyl methacrylate as in Example 9 or adding polyoxyethylene alkyl ether as in Example 10.
The result of Example 10 is good because the side chain portion of methoxypolyethylene glycol methacrylate and polyoxyethylene alkyl ether are highly compatible, so that the amount of polyoxyethylene alkyl ether becomes smaller and a plasticizing effect is obtained. it is conceivable that. This can also be seen from the fact that the plasticizing effect is not obtained in Comparative Example 8 even when polyoxyethylene alkyl ether is added to polymethacrylate not having methoxypolyethylene glycol methacrylate.

According to the present invention, when used in an inorganic fine particle-dispersed paste composition, the inorganic fine particles are excellent in dispersibility, can be degreased even in a low-temperature atmosphere with little residual carbon after sintering, and It is possible to provide a binder resin for dispersing inorganic fine particles, an inorganic fine particle dispersed paste composition, and an inorganic fine particle dispersed paste composition for forming a green sheet capable of obtaining a sheet having high mechanical strength.

Claims (4)

A binder resin for dispersing inorganic fine particles used in an inorganic fine particle dispersed sheet,
A segment derived from a methacrylate having an aliphatic hydrocarbon group having 1 to 4 carbon atoms in the ester portion, and a segment derived from polyethylene glycol monomethacrylate,
The content of segments derived from polyethylene glycol monomethacrylate is 30 to 50% by weight, and
The polyethylene glycol monomethacrylate has a repeating number of ethylene oxide of 20 to 50, and is a binder resin for dispersing inorganic fine particles. An inorganic fine particle-dispersed paste composition comprising the inorganic fine particle-dispersing binder resin according to claim 1 and inorganic fine particles. An inorganic fine particle dispersed sheet using the inorganic fine particle dispersed paste composition according to claim 2. The inorganic fine particle-dispersed sheet according to claim 3, further comprising a nonionic surfactant having polyethylene oxide.

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