RESIN COMPOSITION FOR SINTERING, INORGANIC FINE PARTICLE DISPERSED SLURRY COMPOSITION, AND INORGANIC FINE PARTICLE DISPERSED SHEET

Abstract

The present invention provides a resin composition for sintering, an inorganic fine particle-dispersed slurry composition containing the resin composition for sintering, and an inorganic fine particle-dispersed sheet formed using the resin composition for sintering or inorganic fine particle-dispersed slurry composition. The present invention relates to a resin composition for sintering, containing a binder resin, the binder resin including a (meth)acrylic resin (A), the (meth)acrylic resin (A) having at least one selected from the group consisting of a sulfone group, an alkyl sulfonyl group, an aromatic sulfonyl group, a sulfine group, an imidazoline group, a carboxy group, an amide group, an amino group, and a hydroxy group at at least one molecular end of the main chain and having a weight average molecular weight (Mw) of 1,000,000 or more, an amount of a water-soluble surfactant in the resin composition for sintering being 0 parts by weight or more and 0.02 parts by weight or less per 100 parts by weight of the binder resin.

Claims

1. A resin composition for sintering, comprising a binder resin, the binder resin comprising a (meth)acrylic resin (A), the (meth)acrylic resin (A) having at least one selected from the group consisting of a sulfone group, an alkyl sulfonyl group, an aromatic sulfonyl group, a sulfine group, an imidazoline group, a carboxy group, an amide group, an amino group, and a hydroxy group at at least one molecular end of a main chain and having a weight average molecular weight (Mw) of 1,000,000 or more, an amount of a water-soluble surfactant in the resin composition for sintering being 0 parts by weight or more and 0.02 parts by weight or less per 100 parts by weight of the binder resin.

2. The resin composition for sintering according to claim 1, wherein the (meth)acrylic resin (A) has a glass transition temperature (Tg) of 40° C. or higher.

3. The resin composition for sintering according to claim 1, wherein the (meth)acrylic resin (A) has a CV value of particle size of 10% or lower.

4. The resin composition for sintering according to claim 1, wherein the (meth)acrylic resin (A) comprises 40% by weight or more of a segment derived from isobutyl methacrylate.

5. The resin composition for sintering according to claim 1, wherein the (meth)acrylic resin (A) comprises a segment derived from at least one selected from the group consisting of methyl methacrylate, n-butyl methacrylate, and ethyl methacrylate.

6. The resin composition for sintering according to claim 1, wherein the (meth)acrylic resin (A) has a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 2.0 or less.

7. The resin composition for sintering according claim 1, wherein the (meth)acrylic resin (A) molded into a sheet form having a thickness of 20 .Math.m shows yield stress and has a maximum stress of 30 N/mm.sup.2 or more and an elongation at break of 50% or higher.

8. The resin composition for sintering according to claim 1, further comprising an organic solvent having a boiling point of 70° C. or higher.

9. The resin composition for sintering according to claim 8, wherein the resin composition adjusted to contain 10% by weight of the binder resin has a haze of lower than 10%.

10. An inorganic fine particle-dispersed slurry composition comprising: the resin composition for sintering according to claim 1; and inorganic fine particles.

11. An inorganic fine particle-dispersed sheet formed using the resin composition for sintering according to claim 1 or the inorganic fine particle-dispersed slurry composition according to claim 10.

Description

DESCRIPTION OF EMBODIMENTS

[0205] The present invention is more specifically described in the following with reference to, but not limited to, examples.

Example 1

[0206] A 2-L separable flask equipped with a stirrer, a condenser, a thermometer, a water bath, and a nitrogen gas inlet was provided. The 2-L separable flask was charged with 900 parts by weight of water and monomers including 70 parts by weight of isobutyl methacrylate (iBMA) and 30 parts by weight of ethyl methacrylate (EMA). The contents were stirred with a stirring blade under the condition of 150 rpm, so that monomers were dispersed in water. Thus, a monomer liquid mixture was obtained.

[0207] The obtained monomer liquid mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen. Thereafter, the separable flask system was purged with nitrogen gas, and the temperature was raised with stirring until the water bath reached 80° C. Thereto was added a solution of 0.01 parts by weight of ammonium dodecylsulfonate (DSA, solubility in water at 25° C.: 10 g/100 g) as a water-soluble surfactant and 0.08 parts by weight of ammonium persulfate (APS) as a polymerization initiator in 20 parts by weight of water, thereby initiating polymerization. Seven hours after the start of the polymerization, the contents of the flask were cooled to room temperature to complete the polymerization. Thus, an aqueous solution containing a (meth)acrylic resin having a sulfone group at one molecular end of the main chain was obtained.

[0208] A 2-g portion of the obtained resin aqueous solution wad dried in an oven at 150° C. to determine the resin solid content. The aqueous solution had a resin solid content concentration of 10% by weight and it was confirmed that all the monomers used were reacted.

[0209] The obtained aqueous solution was dried using a spray dryer. Thus, a resin composition for sintering was obtained.

Examples 2 to 14, Comparative Examples 1 to 9

[0210] A resin composition for sintering was obtained as in Example 1, except that the types and amounts of the monomers, water-soluble surfactant, polymerization initiator, chain transfer agent, and polymerization terminator used were changed as shown in Table 1 or 2. The chain transfer agent and the polymerization initiator were added simultaneously with the addition of monomers to water.

[0211] The monomers, water-soluble surfactants, polymerization initiators, chain transfer agents, and polymerization terminators used are listed below.

Monomer

[0212] MMA: methyl methacrylate nBMA: n-butyl methacrylate 2EHMA: 2-ethylhexyl methacrylate iDMA: isodecyl methacrylate HEMA: 2-hydroxyethyl methacrylate MPOMA: methoxypolypropyleneglycol methacrylate

Water-Soluble Surfactant

[0213] DSN: sodium dodecyl sulfonate (solubility in water at 25° C.: 10 g/100 g) PVA: GOHSENOL Z-210 (available from Mitsubishi Chemical Corporation, solubility in water at 25° C.: 30 g/100 g)

Polymerization Initiator

[0214] KPS: potassium persulfate (available from FUJIFILM Wako Pure Chemical Corporation.) NaPS: sodium persulfate (available from FUJIFILM Wako Pure Chemical Corporation.) VA-044: 2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (available from FUJIFILM Wako Pure Chemical Corporation.) V-50: 2,2′-azobis(2-methylpropionamidine)dihydrochloride (available from FUJIFILM Wako Pure Chemical Corporation.) VA-057: 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]tetrahydrate (available from FUJIFILM Wako Pure Chemical Corporation.) VA-086: 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (available from FUJIFILM Wako Pure Chemical Corporation.) PEROYL SA: disuccinic acid peroxide (available from NOF Corporation) PEROYL IPP: isopropyl peroxydicarbonate (available from NOF Corporation)

Polymerization Terminator

[0215] ASB: (allylsulfonyl)benzene AC: allyl octanoate <Chain transfer agent> MESE: 2-mercaptoethanesulfinic acid ethyl ester MPA: 3-mercaptopropionamide

TABLE-US-00001 Monomer Chain transfer agent/ Polymerization terminator Water-soluble surfactant Polymerization initiator iBMA MMA EMA nBMA 2EHMA iDMA HEMA MPOMA MESE MPA ASB AC DSN PVA DSA KPS APS NaPS VA-044 V-50 VA-057 VA-086 PEROYL SA PEROYL IPP Example 1 70 30 0.01 0.08 Example 2 60 40 0.1 Example 3 40 30 30 0.12 Example 4 50 20 30 0.2 Example 5 70 20 10 0.15 Example 6 60 10 20 10 0.01 0.05 Example 7 50 10 20 10 10 0.02 0.03 Example 8 40 5 55 0.01 0.15 Example 9 45 35 20 0.01 0.15 Example 10 50 40 10 0.01 0.02 Example 11 50 40 10 0.01 0.15 Example 12 50 40 10 0.2 0.01 0.2 Example 13 50 40 10 0.2 0.01 0.2 Example 14 50 40 10 0.2 0.01 0.2

TABLE-US-00002 Monomer Chain transfer agent/ Polymerization terminator Water-soluble surfactant Polymerization initiator iBMA MMA EMA nBMA 2EHMA iDMA HEMA MPOMA MESE MPA ASB AC DSN PVA DSA KPS APS NaPS VA-044 V-50 VA-057 VA-086 PEROYL SA PEROYL IPP Comparative Example 1 30 70 0.08 0.3 Comparative Example 2 30 70 1 0.02 Comparative Example 3 30 70 0.03 0.1 Comparative Example 4 30 50 20 0.03 0.2 Comparative Example 5 30 50 20 1 0.2 Comparative Example 6 20 35 45 0.01 0.03 Comparative Example 7 20 35 45 0.03 0.01 0.03 Comparative Example 8 20 35 45 0.01 0.3 Comparative Example 9 20 35 45 0.03 0.05

Evaluation

[0216] The following evaluations were performed on the (meth)acrylic resins and resin compositions for sintering obtained in the examples and comparative examples. Tables 5 and 6 show the results. No evaluations were performed for Comparative Example 2. In Comparative Example 2, since PVA which is a water-soluble surfactant was used, micelles of monomers became big in the reaction system, so that addition of a small amount of polymerization initiator fails to distribute the polymerization initiator to the micelles sufficiently. The monomers therefore could not sufficiently grow to polymers and no (meth)acrylic resin was obtained.

[0217] (1) Z average particle size and CV value of particle size The aqueous solutions containing the (meth)acrylic resins obtained by the polymerization in the examples and comparative examples were each supplied to a Zetasizer for measurement of the particle size. The CV value of particle size was calculated using the following expression. CV value (%) = standard deviation ÷ average particle size × 100

[0218] (2) Average molecular weight The weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene of the obtained (meth)acrylic resin were measured by gel permeation chromatography using a column LF-804 (available from Shoko Science Co., Ltd.).

[0219] (3) Glass transition temperature (Tg) The glass transition temperature (Tg) of the obtained (meth)acrylic resin was measured using a differential scanning calorimeter (DSC). Specifically, the evaluation was performed by heating the (meth)acrylic resin from normal temperature to 150° C. at a rate of temperature rise of 5° C./min in nitrogen atmosphere at a flow rate of 50 mL/min.

[0220] (4) Amount of water-soluble surfactant The amount of the water-soluble surfactant in the obtained resin composition for sintering was calculated based on the amount of decomposition gas at 400° C. to 600° C. derived from combustion of the water-soluble surfactant and the amount of decomposition gas at 200° C. to 300° C. derived from decomposition of the (meth)acrylic resin, using a thermogravimetry mass spectrometer (TG-MS device, available from Netzsch).

[0221] (5) Tensile test The obtained resin composition for sintering was dissolved in a butyl acetate solution to prepare a resin solution. The resin solution was applied to a release-treated PET film with an applicator, and dried in a fan oven at 100° C. for 10 minutes to prepare a resin sheet having a thickness of 20 .Math.m. Graph paper was used as a cover film. A strip-shaped specimen having a width of 1 cm was prepared with scissors.

[0222] The obtained specimen was subjected to a tensile test under the conditions of 23° C. and 50 RH using an autograph AG-IS (available from Shimadzu Corporation) at an inter-chuck distance of 3 cm and a pulling speed of 10 mm/min. The stress-strain chatacteristics (presence or absence of yield stress, measurement of maximum stress and elongation at break) were determined.

[0223] (6) Sinterability (6-1) Preparation of conductive paste Each of the resin composition for sintering obtained in the examples and comparative examples was dissolved in a terpineol solvent to a resin solid content of 11% by weight to give a resin composition solution. To 44 parts by weight of the obtained resin composition solution were added 1 part by weight of oleic acid as a dispersant and 55 parts by weight of nickel powder (“NFP201”, available from JFE Mineral Co., Ltd.) as conductive fine particles. The components were mixed with a triple roll mill to give a conductive paste.

[0224] (6-2) Preparation of ceramic green sheet Each of the resin compositions for sintering obtained in the examples and comparative examples, inorganic fine particles, a plasticizer, and an organic solvent were added according to the formulation in Table 3 or 4, and mixed with a ball mill to give an inorganic fine particle-dispersed slurry composition.

[0225] The obtained inorganic fine particle-dispersed slurry composition was applied to a release-treated polyester film to a dry thickness of 1 .Math.m. The applied slurry was dried at room temperature for one hour, followed by drying at 80° C. for three hours and then at 120° C. for two hours with a hot air dryer. Thus, a ceramic green sheet was prepared.

[0226] Barium titanate (“BT-02”, available from Sakai Chemical Industry Co., Ltd., average particle size: 0.2 .Math.m) was used as the inorganic fine particles and butyl acetate was used as the organic solvent.

TABLE-US-00003 Inorganic fine particle-dispersed slurry composition Resin composition for sintering Plasticizer Organic solvent (parts by weight) Inorganic fine particles (parts by weight) (Meth)acrylic resin (parts by weight) Water-soluble surfactant (parts by weight) Type Amount (parts by weight) Example 1 10 0.001 Triethyl acetylcitrate 1.2 53.8 35 Example 2 10 0 Triethyl acetylcitrate 1.2 53.8 35 Example 3 10 0 Triethyl acetylcitrate 1.2 53.8 35 Example 4 10 0 Triethyl acetylcitrate 1.2 53.8 35 Example 5 10 0 Monomethyl adipate 1.2 53.8 35 Example 6 10 0.001 Monomethyl adipate 1.2 53.8 35 Example 7 10 0.002 Monomethyl adipate 1.2 53.8 35 Example 8 10 0.001 Tripropionin 1.2 53.8 35 Example 9 10 0.001 Diethyl acetylsuccinate 1.2 53.8 35 Example 10 10 0.001 Triacetin 1.2 53.8 35 Example 11 10 0.001 Pentaerythritol tetraacetate 1.2 53.8 35 Example 12 10 0.001 Trimethyl acetylcitrate 1.2 53.8 35 Example 13 10 0.001 Pentaerythritol tetraacetate 1.2 53.8 35 Example 14 10 0.001 Dimethyl methoxymalonate 1.2 53.8 35

TABLE-US-00004 Inorganic fine particle-dispersed slurry composition Resin composition for sintering Plasticizer Organic solvent (parts by weight) Inorganic fine particles (parts by weight) (Meth)acrylic resin (parts by weight) Water-soluble surfactant (parts by weight) Type Amount (parts by weight) Comparative Example 1 10 0.008 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 2 - Comparative Example 3 10 0.003 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 4 10 0.003 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 5 10 0.1 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 6 10 0.001 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 7 10 0.001 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 8 10 0.001 Di(butoxyethyl) adipate 1.2 53.8 35 Comparative Example 9 10 0.003 Di(butoxyethyl) adipate 1.2 53.8 35

3) Preparation of Ceramic Fired Body

[0227] The obtained conductive paste was applied to one surface of the obtained ceramic green sheet to a dry thickness of 1.5 .Math.m by a screen printing method. The paste was dried to form a conductive layer, whereby a ceramic green sheet with a conductive layer was obtained. The obtained ceramic green sheet with a conductive layer was cut to a 5-cm square. One hundred 5-cm square ceramic green sheets were stacked together and pressure-bonded with heat for 10 minutes under the conditions of a temperature of 70° C. and a pressure of 150 kg/cm.sup.2, whereby a laminate was obtained.

[0228] The obtained laminate was heated in a nitrogen atmosphere to 400° C. at a rate of temperature rise of 3° C./min, and held at the temperature for five hours, then heated to 1350° C. at a rate of temperature rise of 5° C./min, and held at the temperature for 10 hours. Thus, a ceramic fired body was prepared.

4) Evaluation on Sinterability

[0229] The obtained ceramic fired body was cut and the cross section was observed with an electron microscope. Evaluation was made based on the following criteria.

[0230] In the case of using the resin composition for sintering of Comparative Example 1 or 4, no laminate was obtained, failing to prepare a ceramic fired body.

[0231] ◯ (Good): The ceramic fired body had no voids, cracks, or peelings, and the layers were bonded to each other.

[0232] × (Poor): The ceramic fired body had voids, cracks, or peelings. The ceramic fired body could not be obtained.

Solution Haze

[0233] The obtained resin composition for sintering was dissolved in butyl acetate to prepare a solution having a resin concentration of 10% by weight. The haze of the solution was measured using a haze meter (“HM-150”, available from Murakami Color Research Laboratory).

Surface Roughness

[0234] The center line average roughness (Ra) of the surface of the ceramic green sheet obtained in “(6) Sinterability” was measured using a stylus-type roughness meter (“SURFCOM 1400D”, available from Tokyo Seimitsu Co., Ltd.) by a method in conformity with JIS B 0601, and evaluated based on the following criteria. The case where Ra was 0.05 .Math.m or less was rated oo (Excellent). The case where Ra was 0.1 .Math.m or less was rated o (Good). The case where Ra was more than 0.1 .Math.m was rated × (Poor).

[0235] ◯ ◯ (Excellent): Ra was 0.05 .Math.m or less.

[0236] ◯ (Good): Ra was more than 0.05 .Math.m but not more than 0.1 .Math.m. × (Poor): Ra was more than 0.1 .Math.m.

TABLE-US-00005 (Meth)acrylic resin Tensile test Sinterability Solution haze Surface roughness (Ra) End structure Resin particle size Average molecular weight Glass transition temperature (Tg) Z average particle size (nm) CV value (%) Mw (million) Mw//Mn (°C) Yield stress Maximum stress (N/mm.sup.2) Elongation at break (%) Judgement Measurement Example 1 Sulfone group (—SO.sub.2—OH) 500 6 5 2.0 56.6 Present 47 290 ◦ 5 ◦ Example 2 Sulfone group (—SO.sub.2—OH) 400 6 3 1.9 40.0 Present 36 210 ◦ 4 ◦◦ Example 3 Imidazoline group 400 6 3 1.8 58.7 Present 43 190 ◦ 4 ◦◦ Example 4 Sulfone group (—SO.sub.2—OH) 200 3 1 1.9 45.5 Present 33 240 ◦ 4 ◦◦ Example 5 Amino group (—C(NH)—NH.sub.2) 300 5 2 2.0 46.0 Present 38 110 ◦ 4 ◦◦ Example 6 Carboxy group (—C(NH)—NHCH.sub.2CH.sub.2—COOH) 500 8 6 1.8 42.2 Present 36 320 ◦ 7 ◦ Example 7 Hydroxy group (—C(O)—NHCH.sub.2CH.sub.2—OH) 600 10 7 2.0 40.8 Present 41 380 ◦ 9 ◦ Example 8 Sulfone group (—SO.sub.2—OH) 400 8 3 1.9 35 Absent 30 200 ◦ 4 ◦ Example 9 Sulfone group (—SO.sub.2—OH) 400 8 3 1.9 65 Present 50 100 ◦ 5 ◦ Example 10 Sulfone group (—SO.sub.2—OH) 400 8 8 2.1 55 Present 48 300 ◦ 11 × Example 11 Sulfone group (—SO.sub.2—OH) 700 10 3 2.1 55 Present 44 200 ◦ 6 ◦ Example 12 Aromatic sulfonyl group (—SO.sub.2—C.sub.6H.sub.5) 300 20 1 2.1 55 Present 38 100 ◦ 4 ◦ Example 13 Sulfine group (—SO—O—C.sub.2H.sub.5) 300 6 1 1.9 55 Present 42 150 ◦ 4 ◦ Example 14 Amide group(—CH.sub.2CH.sub.2—C(O)—NH.sub.2) 300 6 1 1.9 55 Present 42 150 ◦ 4 ◦

TABLE-US-00006 (Meth)acrylic resin Tensile test Sinterability Solution haze Surface roughness (Ra) End structure Resin particle size Average molecular weight Glass transition temperature (Tg) Z average particle size (nm) CV value (%) Mw (million) Mw//Mn (°C) Yield stress Maximum stress (N/mm.sup.2) Elongation at break (%) Judgement Measurement Comparative Example 1 Sulfone group (—SO.sub.2—OH) 100 30 0.5 2.0 89.4 Absent No yield value 10 × 15 × Comparative Example 2 - - - - - Comparative Example 3 Sulfone group (—SO.sub.2—OH) 800 20 3 3.0 29.9 Absent 28 200 × 10 ◦ Comparative Example 4 Sulfone group (—SO.sub.2—OH) 1200 30 1 2.5 72.4 Absent No yield value 18.0 × 10 ◦ Comparative Example5 Sulfone group (—SO.sub.2—OH) 2000 40 1 2.5 52.4 Absent 35 20.0 × 18 × Comparative Example 6 Isopropyl group 2000 50 1 2.0 56 Present 45 80 × 4 ◦ Comparative Example 7 Octyl group 2000 40 1 2.0 56 Present 45 80 × 4 ◦ Comparative Example 8 Sulfone group (—SO.sub.2—OH) 100 6 0.5 2.0 56 Present 42 50 × 3 ◦ Comparative Example 9 Sulfone group (—SO.sub.2—OH) 500 8 5 2.0 56 Present 48 200 × 13 ×

[0237] Examples 1 to 7 were confirmed to have excellent characteristics in every evaluation item. In contrast, Comparative Examples 1 and 4 were brittle in the sheet tensile test to have only small elongation at break. The ceramic green sheets therefore had poor handleability, failing to provide laminates. In Comparative Example 3, the obtained (meth)acrylic resin had a low glass transition temperature (Tg), so that the resulting ceramic green sheet had no resilience and had uneven thickness, resulting in peeling between layers of the ceramic fired body. In Comparative Example 5, voids due to decomposition gas of residual carbon were observed at the center part of the ceramic fired body.

INDUSTRIAL APPLICABILITY

[0238] The present invention can provide a resin composition for sintering which has excellent decomposability at low temperature, can provide a molded article having high strength, and enables an increase in the number of layers and thinning so as to enable production of a ceramic laminate having excellent properties. The present invention can provide an inorganic fine particle-dispersed slurry composition containing the resin composition for sintering, and an inorganic fine particle-dispersed sheet formed using the resin composition for sintering or the inorganic fine particle-dispersed slurry composition.