JP5095377B2 - Binder resin for inorganic fine particle dispersed paste composition, inorganic fine particle dispersed paste composition, inorganic fine particle dispersed paste composition for forming green sheet, and green sheet - Google Patents

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, an inorganic fine particle dispersed paste composition, an inorganic fine particle dispersed paste composition for forming a green sheet, and a green sheet capable of obtaining a green sheet having high strength.

In recent years, an inorganic fine particle-dispersed paste composition in which inorganic fine particles such as conductive powder, ceramic powder, and glass particles are dispersed in a binder resin has been used to obtain fired bodies having various shapes. For example, a paste composition in which metal fine particles are dispersed as a conductive powder is used for circuit formation, capacitor production, etc., and ceramic paste or glass paste in which ceramic powder or glass particles are dispersed is a plasma display panel (hereinafter, (Also referred to as PDP) for manufacturing dielectric layers and multilayer ceramic capacitors.

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.

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 forming an internal electrode using a conductive paste mainly composed of such a base metal material, it is necessary to perform a debinding process and a baking process of 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.

Therefore, it has been studied to use an acrylic resin excellent in low-temperature decomposability as a binder. 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, physical properties such as sheet strength, sheet elongation, and sheet forming density 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. Another object of the present invention is to provide a binder resin, an inorganic fine particle-dispersed paste composition, and an inorganic fine particle-dispersed paste composition for forming a green sheet capable of obtaining a green sheet having high mechanical strength.

The present invention relates to a binder resin for an inorganic fine particle dispersed paste composition used for an inorganic fine particle dispersed paste composition containing inorganic fine particles, a segment derived from methyl methacrylate, a segment derived from isobutyl methacrylate, and polyethylene glycol mono The segment derived from methacrylate has a segment derived from methyl methacrylate of 30 to 35 % by weight, the segment derived from isobutyl methacrylate of 40 to 50 % by weight, and the segment derived from polyethylene glycol monomethacrylate. The polyethylene glycol monomethacrylate having a content of 15 to 30% by weight is a binder resin for an inorganic fine particle dispersed paste composition in which the number of ethylene oxide repeats is 30 or more.
The present invention is described in detail below.

As a result of intensive studies, the present inventors were surprised when isobutyl methacrylate and polyoxyalkylene ether monomethacrylate were added with methyl methacrylate to form a copolymer, and the ratio of polyoxyalkylene ether monomethacrylate was within a predetermined range. As a matter of fact, the present inventors have found that a remarkable improvement is observed in the thermal decomposition property, which has been predicted to deteriorate, and that the decomposition time is significantly shortened particularly when heated at 300 ° C. In addition, it has been found that when the binder resin having such a configuration is used, generation of soot during combustion is suppressed, and residual carbon after sintering can be reduced. However, a molded product obtained using such a binder resin has brittle physical properties and is difficult to use for ceramic green sheets and the like.
Therefore, as a result of further intensive studies, the present inventors have used polyethylene glycol monomethacrylate as the polyoxyalkylene ether monomethacrylate, and further increased the number of ethylene oxide repeats to 30 or more, thereby dramatically increasing the elongation characteristics of the resin. As a result, the present invention has been completed.

FIG. 1 shows a copolymer consisting of (A) methyl methacrylate (MMA) homopolymer; (B) isobutyl methacrylate (IBMA) homopolymer; (C) 70% by weight of IBMA and 30% by weight of polypropylene glycol monomethacrylate (PPGMA). It is a graph which shows the decomposition characteristic (TG * DTA) at the time of raising the temperature from 0 degreeC to 600 degreeC, (D) Copolymer which consists of 30 weight% of MMA, 60 weight% of IBMA, and 10 weight% of PPGMA.
As shown in FIG. 1, (A) is inferior in thermal decomposability compared to (B) and (C), and in particular, the thermal decomposability at a temperature of 300 ° C. or higher is extremely poor. Yes.
However, MMA is added to (C) to form a copolymer with a predetermined ratio, and (D) has a greatly improved thermal decomposability at a temperature of 300 ° C. or higher, and particularly has an extremely high decomposition property near 300 ° C. It turns out that it is excellent. In (A), the higher order structure of the polymer affects the decomposition behavior and the thermal decomposition temperature becomes higher. In addition to combining the above three types of segments, the content of each segment is set to a predetermined amount. This is considered to be because the low-temperature decomposition characteristics inherent to methyl methacrylate can be sufficiently exhibited.

FIG. 2 shows a case where the weight average molecular weight of a copolymer composed of 30% by weight of methyl methacrylate (MMA), 60% by weight of isobutyl methacrylate (IBMA) and 10% by weight of polypropylene glycol monomethacrylate (PPGMA) is changed. It shows the elongation characteristics. The case where the weight average molecular weight (Mw) was 250,000 was (A), the case where Mw was 150,000 was (B), and the case where Mw was 80,000 was (C).
As shown in FIG. 2, the stress at break depends on the weight average molecular weight of the copolymer, and the sample breaks before the yield point.

FIG. 3 is a graph showing tensile properties when methoxypolyethylene glycol methacrylate (MPEGMA, 30 repetitions) is used in place of polypropylene glycol monomethacrylate. A case of using a copolymer having 40% by weight of MMA, 45% by weight of IBMA and 15% by weight of MPEGMA, and Mw of 110,000 (A); 34% by weight of MMA, 39% by weight of IBMA, 27% by weight of MPEGMA, and 50,000 of Mw. The case where a polymer was used was defined as (B). As shown in FIG. 3, it can be seen that the elongation property of the resin is remarkably improved in (B) than in (A). Therefore, when the MPEGMA component is used, the elongation characteristics can be improved regardless of the weight average molecular weight. In particular, when 20% by weight or more of methoxypolyethylene glycol methacrylate is added, the elongation characteristics of the copolymer are improved. Thus, it is thought that it is derived from the structure of polyethylene oxide that the elongation property of the copolymer is improved.

The binder resin of the present invention has a segment derived from methyl methacrylate, a segment derived from isobutyl methacrylate, and a segment derived from polyethylene glycol methacrylate. By having the above three types of segments and the content of the segment derived from polyethylene glycol methacrylate as a predetermined amount, for example, when used as a binder resin for a green sheet, the resulting green sheet has an elongation property. In addition, it is possible to achieve degreasing at a low temperature and to reduce residual carbon after sintering.
In the present specification, low temperature degreasing means that 99.5% by weight or more of the initial weight of the binder resin is decomposed when held at 300 ° C. for 1 hour in a normal air atmosphere in which nitrogen substitution or the like is not performed. Means that.

The binder resin of the present invention contains a segment derived from methyl methacrylate and a segment derived from isobutyl methacrylate.
Methyl methacrylate is inherently a material that decomposes at a low temperature, but its higher-order structure serves to increase the decomposition temperature. Therefore, copolymerization with isobutyl methacrylate eliminates the higher order structure of methyl methacrylate and enables low-temperature decomposition. The thermal decomposition mode of the segments derived from methyl methacrylate and isobutyl methacrylate is depolymerization, and the decomposition volatiles are the respective monomers.

Further, methyl methacrylate has a function of reducing the molecular weight of a decomposition gas generated when copolymerized with a polyalkylene ether, and is considered to have a function of suppressing adsorption of decomposition products on the surface of inorganic fine particles after degreasing.

The minimum with preferable content of the segment originating in the methyl methacrylate in the binder resin of this invention is 10 weight%, and a preferable upper limit is 60 weight%. If it is less than 10% by weight, the Tg of the binder resin becomes low and the sheet becomes soft, so that the handleability may be deteriorated. If it exceeds 60% by weight, the decomposition end temperature may increase.

The binder resin of the present invention has a segment derived from isobutyl methacrylate.
By having the segment derived from the isobutyl methacrylate, the low-temperature decomposition characteristic originally possessed by the segment derived from methyl methacrylate can be sufficiently exhibited.
In general, as the number of carbon atoms in the acrylic side chain increases, the thermal decomposition temperature of the resin increases, but the combination of the segment derived from methyl methacrylate and the segment derived from isobutyl methacrylate is the most thermal decomposition temperature among the few carbon atoms. Can be reduced.

The minimum with preferable content of the segment originating in the isobutyl methacrylate in the binder resin of this invention is 10 weight%, and a preferable upper limit is 70 weight%. If it is less than 10% by weight, the decomposition end temperature may increase. If it exceeds 70% by weight, the Tg of the binder resin becomes low and the sheet becomes soft, so that the handleability is deteriorated.

In order to prevent an increase in the thermal decomposition temperature due to the higher order structure of the segment derived from methyl methacrylate, the ratio of the segment derived from isobutyl methacrylate is preferably larger than the ratio of the segment derived from methyl methacrylate. .

The binder resin 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.

The polyethylene glycol (meth) acrylate is not particularly limited, and examples thereof include methoxyethylene glycol monomethacrylate, methoxyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol-polypropylene glycol mono (meth) acrylate, and the like. Copolymers of polyethylene glycol and other types of polyethers with a high polyethylene glycol composition ratio and crystallinity, and those having an alkyl group at the end of polyethylene glycol such as lauroxy polyethylene glycol mono (meth) acrylate Can be mentioned.

The lower limit of the number of ethylene oxide repeats of the polyethylene glycol monomethacrylate is 30. If it is less than 30, the crystallinity does not appear and it does not work as a pseudo-crosslinking point, so the elongation characteristics may not be improved.

The minimum of content of the said polyethyleneglycol (meth) acrylate is 15 weight%, and an upper limit is 30 weight%. When it is less than 15% by weight, when polyethylene glycol (meth) acrylate having a relatively small number of ethylene oxide repeats is used, polyethylene oxide derived from other polymers forms a eutectic in the crystallized polyethylene oxide domain. Since the possibility becomes low and it does not work as a pseudo-crosslinking point, the desired elongation characteristic is not sufficiently exhibited, and when it exceeds 30% by weight, gelation or the like tends to occur during polymerization. Therefore, the longer the number of ethylene oxide repeats, the lower the polyethylene glycol monomethacrylate content.

In addition to the segment derived from the above methyl methacrylate, the segment derived from isobutyl methacrylate, and the segment derived from polyoxyalkylene ether monomethacrylate, the binder resin of the present invention adds desired functionality. You may have the segment derived from the monomer which has a polar group in the range which does not impair an effect.

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

When it has the segment derived from the monomer which has the said polar group, it is preferable that content of the segment derived from the monomer which has the said polar group is less than 5 weight%. If it is 5% by weight or more, thermal decomposability at low temperatures may be impaired, soot that adheres to the inorganic fine particles may increase, and residual carbon in the sintered body may increase.

The binder resin 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 of the present invention, the preferable lower limit of the weight average molecular weight in terms of polystyrene is 20,000, and the preferable upper limit is 1,000,000. If it is less than 20,000, viscosity may not be sufficiently obtained and storage stability may deteriorate. If it exceeds 1,000,000, problems may occur in the stringiness and solubility in a solvent of the resulting inorganic fine particle dispersed paste composition.
In addition, the measurement of the number 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.

The method for producing the binder resin of the present invention is not particularly limited. For example, after preparing a monomer mixed solution containing methyl methacrylate, isobutyl methacrylate and polyethylene glycol monomethacrylate as raw materials and containing a chain transfer agent and an organic solvent. And a method of adding a polymerization initiator to the monomer mixed solution and copolymerizing the raw material monomers.

Further, as a method for introducing a hydrogen bonding functional group only to the molecular terminal of the binder resin of the present invention, for example, the above-mentioned methyl methacrylate, isobutyl methacrylate and polyethylene under a chain transfer agent having a hydrogen bonding functional group. Raw material monomers consisting of glycol monomethacrylate are copolymerized by conventionally known methods such as free radical polymerization method, living radical polymerization method, iniferter polymerization method, anion polymerization method, living anion polymerization method, and hydrogen bonding functional groups. Examples thereof include a method of copolymerizing the above-described monomers under a polymerization initiator having a conventionally known method such as a free radical polymerization method, a living radical polymerization method, an iniferter polymerization method, an anionic polymerization method, or a living anion polymerization method. . These methods may be used in combination.
Moreover, it can be confirmed by, for example, ¹³ C-NMR that a hydrogen bonding functional group is introduced only at the molecular terminal of the binder resin.

The chain transfer agent having a hydrogen bonding functional group is not particularly limited. For example, mercaptopropanediol having a hydroxyl group as a hydrogen bonding functional group, thioglycerol having a carboxyl group as a hydrogen bonding functional group, 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, and examples thereof include 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.

In addition, an inorganic fine particle-dispersed paste composition can be prepared using the binder resin of the present invention, an organic solvent, and inorganic fine particles.
The inorganic fine particle-dispersed paste composition containing the 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, alumina, zirconia, titanium oxide, barium titanate, alumina nitride, silicon nitride, boron nitride, silicate glass, lead glass, CaO. Low melting point glass such as Al ₂ O ₃ · SiO ₂ inorganic glass, MgO · Al ₂ O ₃ · SiO ₂ inorganic glass, LiO ₂ · Al ₂ O ₃ · SiO ₂ inorganic glass, BaMgAl ₁₀ O ₁₇ : Eu, Examples thereof include phosphors such as Zn ₂ SiO ₄ : Mn and (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, and 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, 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, benzyl alcohol, phenylpropylene 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 organic solvent preferably has a boiling point of 150 ° C. or higher. If it is lower than 150 ° C., the solvent volatilizes during the printing process, the viscosity of the paste increases, and printing may not be possible.

Although it does not specifically limit as content of the binder resin in the inorganic fine particle dispersion paste composition of this invention, A preferable minimum is 5 weight% and a preferable upper limit is 30 weight%. When the content of the binder resin 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, those obtained by adding an alkylene ether to a fatty chain are preferable, and specifically, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and the like are preferably used. 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 glass powder is used as the inorganic fine particles. In addition, when ceramic powder is used as the inorganic fine particles, a ceramic paste composition is used. When phosphor powder is used as the inorganic fine particles, a phosphor paste composition is used. When conductive powder is used as the inorganic fine particles, a conductive paste composition is used. It can be preferably used.

By using glass powder or ceramic powder as the inorganic fine particles, it can be suitably used as a material for the green sheet. 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. Such an inorganic fine particle-dispersed paste composition for forming a green sheet is also one aspect of the present invention.

As the solvent used in the inorganic fine particle dispersed paste composition for forming a green sheet of the present invention, toluene, butyl acetate, isopropanol, methyl isobutyl ketone and the like are particularly preferable. The amount of the solvent added is preferably selected as appropriate depending on the coating process used, and is not particularly limited. Further, the content of the inorganic fine particles and the inorganic fine particles in the inorganic fine particle-dispersed paste composition for forming a green sheet of the present invention is not particularly limited, but a preferable lower limit is 50% by weight and a preferable upper limit is 95% by weight. If it is less than 50% by weight, there is a possibility that a large amount of resin is present and a problem may occur in the sinterability.

A green sheet can be produced by applying the inorganic fine particle-dispersed paste composition for forming a green sheet of the present invention onto a support film that has been subjected to a single-sided release treatment, drying the solvent, and forming into a sheet shape. . Such a green sheet is also one aspect of the present invention.
As a method for producing the green sheet of the present invention, for example, the binder resin of the present invention is dissolved in a solvent, a surfactant, a dispersing agent, a plasticizer, etc. are added, stirred, a uniform vehicle is prepared, and then inorganic fine particles are prepared. And uniformly dispersed using a ball mill dispersing apparatus. 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 for forming a green sheet 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 green sheet of the present invention is preferably a resin film having heat resistance and solvent resistance and flexibility. Since the support film is flexible, the inorganic fine particle dispersed paste composition for forming a green sheet can be applied to the surface of the support film by a roll coater, a blade coater, or the like, and the resulting green sheet forming film is rolled. It 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 A binder resin, an inorganic fine particle dispersed paste composition, an inorganic fine particle dispersed paste composition for forming a green sheet, and a green sheet capable of obtaining a green sheet having high mechanical strength can be provided.

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, 30 parts by weight of methyl methacrylate (MMA), isobutyl methacrylate (IBMA) 45 parts by weight, methoxypolyethylene glycol monomethacrylate (MPEGMA, Kyoeisha Chemical Co., Ltd. light ester 041MA, PEO repeat number 30) 25 parts by weight, chain transfer agent dodecyl mercaptan, organic solvent 100 parts by weight butyl acetate As a result, a monomer mixture was obtained.

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.
50 parts by weight of alumina (average particle diameter 2.0 μm) as inorganic powder is added to 50 parts by weight of the butyl acetate solution of the (meth) acrylic resin thus obtained, and the mixture is 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 solvent was removed by drying the formed coating film at 100 ° C. for 10 minutes to form an inorganic powder-containing resin layer having a thickness of 50 μm on the support film. Next, a green sheet was manufactured by pasting a cover film (width 400 mm, length 30 m, thickness 25 μm) made of PET, which was previously subjected to mold release treatment, on the inorganic powder-containing resin layer.

(Examples 2-4, Comparative Examples 1-6)
The composition of the acrylic monomer mixture in Example 1 was changed to the contents shown in Table 1, and an inorganic fine particle dispersed paste composition and a green sheet were produced in the same manner as in Example 1.
The methoxy polyethylene glycol monomethacrylate (MPEGMA) used in Example 2 and Comparative Examples 1, 2, 5, and 6 is the same as that in Example 1. In Examples 3 and 4, MPEGMA having an ethylene oxide repeat number of 90 (manufactured by NOF Corporation, Blemmer PM E 4000), and in Comparative Example 3, MPEGMA having an ethylene oxide repeat number of 23 (manufactured by NOF Corporation, Blemmer PM). E 1000) and Comparative Example 4, MPEGMA having 9 ethylene oxide repeats (Kyoeisha Chemical Co., Ltd., Light Ester 130MA) was used.

<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 4 and Comparative Examples 1 to 6. The results are shown in Table 2.

(1) Resin extensibility The PET film obtained by releasing the butyl acetate solution of the methacrylic resin prepared in Examples and Comparative Examples was applied with a thickness of 0.2032 mm ( 8 mils ) using an applicator and blown at 100 ° C. A resin sheet was prepared by drying in an oven for 10 minutes. Graph paper was used as a cover film, and a strip of 1 cm width was produced with scissors. A tensile test was performed under the conditions of 23 ° C. and 50 RH using an autograph AG-IS manufactured by Shimadzu Corporation at a distance between chucks of 3 cm and a tensile speed of 10 mm / min to evaluate the strain required for breaking.
A product having a breaking strain of 50% or more was evaluated as “◯”, and a product having a fracture strain of less than 50% was evaluated as “×”.

(2) Sinterability The green sheets produced in Examples and Comparative Examples were transferred to a glass substrate, heated to 300 ° C. at 10 ° C./min in a muffle furnace purged with nitrogen, and 1 at 300 ° C. The time was maintained and the sintering was finished. The green sheet was taken out of the muffle furnace and visually checked for baked color.
The thing without coloring was evaluated as ◎, the pale yellow as ◯, and the brown as ×.

(3) Rewindability test A PET sheet, which was release-treated on one side, was bonded to the green sheets prepared in Examples and Comparative Examples as a protective film to prepare a glass sheet.
The obtained glass sheet was wound around a polypropylene pipe having a diameter of 15 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. The thing in which the crack had generate | occur | produced was set to x, and the thing which did not generate | occur | produce was set to (circle).

As shown in Table 2, in the binder resin and the green sheet obtained in the example, good results were obtained.
On the other hand, Comparative Examples 1 and 2 in which either methyl methacrylate or isobutyl methacrylate is not blended are poor in sinterability at 300 ° C., and Comparative Examples 3 and 4 using methoxypolyethylene glycol methacrylate having a small ethylene oxide repeat number. Comparative Example 5 with a small amount of methoxypolyethylene glycol added had poor resin elongation properties, and as a result, it was confirmed that cracks occurred during winding evaluation and were not suitable for the sheet composition. In Comparative Example 6 in which the composition ratio of methoxypolyethyleneglycol methacrylate was increased, a large amount of wrinkles adhered to the sintered body, and it was confirmed that it was not suitable for the sheet.

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, an inorganic fine particle dispersed paste composition, and an inorganic fine particle dispersed paste composition for forming a green sheet, which can obtain a green sheet having high mechanical strength.

It is a graph which shows the thermal decomposition behavior (TG * DTA) of various acrylic copolymers. It is a graph which shows the expansion | extension characteristic of various acrylic copolymers. It is a graph which shows the expansion | extension characteristic of various acrylic copolymers.

Claims (4)

A binder resin for an inorganic fine particle dispersed paste composition used for an inorganic fine particle dispersed paste composition containing inorganic fine particles,
A segment derived from methyl methacrylate, a segment derived from isobutyl methacrylate, and a segment derived from polyethylene glycol monomethacrylate,
The content of segments derived from methyl methacrylate is 30 to 35 % by weight, the content of segments derived from isobutyl methacrylate is 40 to 50 % by weight, and the content of segments derived from polyethylene glycol monomethacrylate is 15 to 30% by weight. Yes, and
The polyethylene glycol monomethacrylate has a repeating number of ethylene oxide of 30 or more, and is a binder resin for inorganic fine particle dispersed paste composition. A binder resin for an inorganic fine particle dispersed paste composition according to claim 1, wherein the inorganic fine particle dispersed paste composition is used. An inorganic fine particle dispersed paste composition for forming a green sheet, comprising the binder resin for an inorganic fine particle dispersed paste composition according to claim 1 or the inorganic fine particle dispersed paste composition according to claim 2. A green sheet comprising the inorganic fine particle dispersed paste composition for forming a green sheet according to claim 3.

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