RESIN COMPOSITION FOR CERAMIC GREEN SHEET, CERAMIC GREEN SHEET, AND LAYERED CERAMIC CAPACITOR

Abstract

The present invention provides a resin composition for a ceramic green sheet capable of providing a ceramic green sheet that has high mechanical strength even with small thickness and is less likely to have appearance defects after cutting or dimensional changes after drying, and a ceramic green sheet and a multilayer ceramic capacitor each produced using the resin composition for a ceramic green sheet. Provided is a resin composition for a ceramic green sheet, the resin composition containing a polyvinyl acetal resin, the resin composition having a tan δ peak top of 1.25 or more and a loss modulus E″ of 2.30×10.sup.8 Pa or more.

Claims

1. A resin composition for a ceramic green sheet, the resin composition comprising a polyvinyl acetal resin, the resin composition having a tan δ peak top of 1.25 or more and a loss modulus E″ of 2.30×10.sup.8 Pa or more.

2. The resin composition for a ceramic green sheet according to claim 1, wherein the polyvinyl acetal resin has a hydroxy group half-width in terms of mol % of 0.01 to 0.15 mol %/cm.sup.−1 as determined by NMR measurement and IR measurement.

3. The resin composition for a ceramic green sheet according to claim 1, further comprising a plasticizer in an amount of 25 parts by weight or less relative to 100 parts by weight of the polyvinyl acetal resin.

4. The resin composition for a ceramic green sheet according to claim 1, wherein the polyvinyl acetal resin is an acetalized product of a polyvinyl alcohol resin having a degree of saponification of 75 mol % or more.

5. The resin composition for a ceramic green sheet according to claim 1, wherein the polyvinyl acetal resin has an acetal group content of 45 to 83 mol %.

6. The resin composition for a ceramic green sheet according to claim 1, wherein the polyvinyl acetal resin has an average degree of polymerization of 1,000 to 10,000.

7. A ceramic green sheet produced using the resin composition for a ceramic green sheet according to claim 1.

8. A multilayer ceramic capacitor comprising the ceramic green sheet according to claim 7.

Description

DESCRIPTION OF EMBODIMENTS

[0076] The present invention is more specifically described in the following with reference to, but not limited to, examples.

EXAMPLE 1

(Production of Polyvinyl Acetal Resin)

[0077] An amount of 2,700 g of pure water was added to 250 g of a polyvinyl alcohol resin having an average degree of polymerization of 1,000, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1, and they were stirred at 90° C. for about two hours for dissolution. This solution was cooled to 40° C., and to the solution were added 100 g of hydrochloric acid having a concentration of 35% by weight and 115 g of n-butyraldehyde to perform acetalization, whereby a reaction product was precipitated. Thereafter, the acetalization was completed at 40° C., followed by neutralization, washing with water, and drying by common methods. Thus, white powder of a polyvinyl acetal resin was obtained.

[0078] The obtained polyvinyl acetal resin was dissolved in DMSO-d.sub.6 at a concentration of 10% by weight. The acetal group content, the hydroxy group content, and the acetyl group content were measured by .sup.13C-NMR. Here, the hydroxy group half-width of the polyvinyl alcohol resin was measured using HORIBA FT-720 (produced by Horiba, Ltd.).

(Production of Resin Composition for Ceramic Green Sheet)

[0079] An amount of 10.0 parts by weight of the obtained polyvinyl acetal resin and 1.0 part by weight of DOP as a plasticizer were added to 45.0 parts by weight of an ethanol/toluene solvent mixture (weight ratio 1:1). They were stirred for dissolution, whereby a resin composition for a ceramic green sheet was obtained.

(Production of Resin Sheet)

[0080] The obtained resin composition for a ceramic green sheet was applied using a coater onto a release-treated PET film to a dried thickness of 15 μm, and then heated and dried at 70° C. for 120 minutes, whereby a resin sheet was obtained.

EXAMPLE 2

(Production of Polyvinyl Acetal Resin)

[0081] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 3

(Production of Polyvinyl Acetal Resin)

[0082] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 3,300, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 4

(Production of Polyvinyl Acetal Resin)

[0083] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 4,900, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 5

(Production of Polyvinyl Acetal Resin)

[0084] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 moll, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 6

(Production of Polyvinyl Acetal Resin)

[0085] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 7

(Production of Polyvinyl Acetal Resin)

[0086] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 8

(Production of Polyvinyl Acetal Resin)

[0087] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 5,000, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 9

(Production of Polyvinyl Acetal Resin)

[0088] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 9,200, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 10

(Production of Polyvinyl Acetal Resin)

[0089] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 8,000, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

EXAMPLE 11

(Production of Polyvinyl Acetal Resin)

[0090] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 350 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 1

[0091] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 600, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 2

[0092] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 4,900, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 3

[0093] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 1,700, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 4

[0094] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 3,300, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 5

[0095] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 4,900, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 6

[0096] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 9,000, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

COMPARATIVE EXAMPLE 7

[0097] A polyvinyl acetal resin, a resin composition for a ceramic green sheet, and a resin sheet were produced as in

[0098] Example 1 except that 250 g of a polyvinyl alcohol resin having a degree of polymerization of 9,000, a degree of saponification of 98.5 mol %, and a hydroxy group half-width of 335 cm.sup.−1 was used.

(Evaluation)

[0099] The polyvinyl acetal resins, resin compositions for a ceramic green sheet, and resin sheets obtained in the examples and the comparative examples were evaluated as follows. Table 1 shows the results.

(1) Determination of Half-Width in Terms of Mol %

[0100] The hydroxy group half-width of each of the polyvinyl acetal resins obtained in the examples and the comparative examples was measured by IR measurement using HORIBA FT-720 (produced by Horiba, Ltd.). From the hydroxy group half-width measured by IR measurement and the hydroxy group content measured by .sup.13C-NMR, the hydroxy group half-width in terms of mol % was determined for the polyvinyl acetal resin.

(2) Tan δ and Loss Modulus E″

[0101] The obtained resin sheet was cut into a size of 0.5 cm×2.0 cm to prepare a specimen, and then the specimen was subjected to dynamic viscoelasticity measurement using a DMA (produced by IT Measurement Co., Ltd.) under the following conditions.

[0102] The tan δ (loss tangent) value used was the value at the peak-top temperature. Similarly, the storage modulus E′ and loss modulus E″ values were measured at the peak-top temperature. The difference between the peak-top temperature of the tan δ and the peak-top temperature of the loss modulus E″ (difference in peak-top temperature: [peak-top temperature of tan δ]−[peak-top temperature of loss modulus E″]) was calculated.

(Measurement Conditions)

[0103] Measurement mode: tensile mode [0104] Forced. oscillation frequency: 1 Hz [0105] Temperature range: 30° C. to 150° C. [0106] Temperature increase rate: 6° C./min

(3) Tensile Modulus of Elasticity, Elongation at Break, and Stress at Break

(Production of Ceramic Green Sheet)

[0107] One part by weight of a polyvinyl acetal resin (produced by Sekisui Chemical Co., Ltd., BL-1) was added to a solvent mixture of 20 parts by weight of toluene and 20 parts by weight of ethanol, and they were stirred for dissolution. Subsequently, to the obtained solution was added 100 parts by weight of barium titanate powder (produced by Sakai Chemical Industry Co., Ltd., BT01, average particle size 0.1 μm), followed by stirring in a bead mill (produced by AIMEX Co., Ltd., Ready Mill) for 180 minutes, whereby an inorganic dispersion was prepared.

[0108] To the obtained inorganic dispersion was added the resin composition for a ceramic green sheet. After stirring in a bead mill for 90 minutes, the mixture was applied using a coater onto a release-treated PET film to a dried thickness of 20 μm, and then heated and dried at 40° C. for 30 minutes. The PET film was removed, whereby a ceramic green sheet was obtained.

[0109] The tensile modulus of elasticity (MPa), elongation at break (%), and stress at break (MPa) of the obtained ceramic green sheet were measured in conformity with JIS K 7113 using a tensile tester (produced by Shimadzu Corporation, AUTOGRAPH AGS-J) at a tensile speed of 20 mm/min.

(4) Section State

[0110] The fracture surface after the measurement of “(3) Tensile modulus of elasticity, elongation at break, and stress at break” was observed with an SEM, and evaluated in accordance with the following criteria. [0111] ∘∘ (Excellent): The fracture surface was not chipped, cracked, or scratched. [0112] ∘ (Good): The fracture surface was not chipped or cracked, but was scratched. [0113] Δ (Fair): The fracture surface was not chipped but was cracked. [0114] × (Poor): The fracture surface was chipped.

(5) Dimensional Change Rate

[0115] A ceramic green sheet was produced as in “(3) Tensile modulus of elasticity, elongation at break, and stress at break”. The obtained ceramic green sheet was dried at 70° C. for three hours. The dimensional change rate before and after the drying at 70° C. was calculated and evaluated in accordance with the following criteria. [0116] ∘∘ (Excellent): not higher than 2% [0117] ∘ (Good): higher than 2% and not higher than 3% [0118] Δ (Fair): higher than 3% and not higher than 4% [0119] × (Poor): higher than 4%

TABLE-US-00001 TABLE 1 Polyvinyl acetal resin Hydroxy Evaluation group Polyvinyl acetal resin film evaluation Acetal Acetyl Hydroxy half-width Tan δ-E″ group group group in terms difference Degree of content content content of mol % E″ in peak polymerization (mol %) (mol %) (mol %) (mol %/cm .sup.1) Tan δ [Pa] temperature Example 1  1000 65.0 1.5 33.5 0.142 1.55 2.30 × 10  14.8 Example 2  1700 65.0 1.5 33.5 0.137 1.97 2.33 × 10  13.1 Example 3  3300 65.0 1.5 33.5 0.140 2.33 2.36 × 10  13.0 Example 4  4900 65.0 1.5 33.5 0.138 2.39 2.38 × 10  12.6 Example 5  1700 65.0 1.0 34.0 0.100 2.01 2.35 × 10  12.8 Example 6  1700 65.0 2.2 32.8 0.148 1.88 2.30 × 10  13.5 Example 7  1700 78.0 1.5 21.5 0.140 1.80 2.30 × 10  14.0 Example 8  5000 65.0 1.5 33.5 0.145 2.40 2.32 × 10  12.2 Example 9  9200 65.0 1.5 33.5 0.140 2.36 2.31 × 10  10.0 Example 10 8000 65.0 1.5 33.5 0.144 2.39 2.38 × 10  11.0 Example 11 1700 50.5 1.5 48.0 0.148 1.30 2.36 × 10  14.7 Comparative  600 65.0 1.5 33.6 0.152 1.00 2.29 × 10  16.2 Example 1  Comparative 4900 65.0 1.5 33.5 0.137 2.40 2.29 × 10  14.5 Example 2  Comparative 1700 65.0 1.5 33.5 0.153 2.28 2.19 × 10  15.2 Example 3  Comparative 3300 65.0 1.5 33.5 0.165 1.23 2.22 × 10  15.0 Example 4  Comparative 4900 65.0 1.5 33.5 0.159 1.22 2.21 × 10  14.9 Example 5  Comparative 9000 76.5 1.5 22.0 0.165 1.20 2.28 × 10  14.3 Example 6  Comparative 9000 58.0 1.5 40.5 0.170 1.21 2.22 × 10  14.1 Example 7  Evaluation Polyvinyl acetal resin film evaluation GS evaluation Stress at Modulus of Elongation Stress at Modulus of Elongation Section state break elasticity at break break elasticity at break SEM Dimensional [MPa] [MPa] [%] [MPa] [MPa] [%] observation change rate Example 1  60  950 280 27  910 15 Example 2  75  900 410 32 1050 23 Example 3  85  900 370 34 1080 23 Example 4  85  955 280 38 1100 25 Example 5  77  940 400 33 1080 24 Example 6  74  890 420 31 1050 22 Example 7  70  880 435 33 1000 25 Example 8  88  910 410 38 1190 28 Example 9  92  890 440 41 1190 30 Example 10 90  900 425 40 1200 30 Example 11 77 1010 190 30 1000 17 Comparative 35  410 250 19  880 13 x Example 1  Comparative 56  800 245 29  995 26 Example 2  Comparative 70  720 300 25  900 15 Example 3  Comparative 75  750 330 26 1000 23 Example 4  Comparative 78  780 350 28  900 25 x Example 5  Comparative 80  820 375 30  900 23 x Example 6  Comparative 77  800 310 31 1000 20 x Example 7  indicates data missing or illegible when filed

INDUSTRIAL APPLICABILITY

[0120] The present invention can provide a resin composition for a ceramic green sheet capable of providing a ceramic green sheet that has high mechanical strength even with small thickness and is less likely to have appearance defects after cutting or dimensional changes after drying, and a ceramic green sheet and a multilayer ceramic capacitor each produced using the resin composition for a ceramic green sheet.