EPOXY RESIN COMPOSITION

Abstract

The present invention provides an epoxy resin composition capable of exhibiting high moisture resistance and reducing reduction in adhesion at high temperature and high humidity. Provided is an epoxy resin composition containing: a modified polyvinyl acetal resin containing a hydrogen-bonding group-containing constitutional unit; and an epoxy resin, the modified polyvinyl acetal resin having an equilibrium moisture absorption of 5 to 20% by weight as measured with an infrared moisture meter after standing at 40° C. and 90% RH for seven days.

Claims

1. An epoxy resin composition comprising: a modified polyvinyl acetal resin containing a hydrogen-bonding group-containing constitutional unit; and an epoxy resin, the modified polyvinyl acetal resin having an equilibrium moisture absorption of 5 to 20% by weight as measured with an infrared moisture meter after standing at 40° C. and 90% RH for seven days.

2. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains the hydrogen-bonding group-containing constitutional unit having an SP value of 11.0 to 18.5.

3. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains a hydroxyl group in an amount of 10.0 to 50.0 mol %.

4. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains the hydrogen-bonding group-containing constitutional unit in an amount of 5.1 to 30.0 mol %.

5. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains a hydroxyl group and the hydrogen-bonding group-containing constitutional unit in a total amount of 15.1 to 65.0 mol %.

6. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin has an average degree of polymerization of 150 to 6,000.

7. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains an acetal group in an amount of 35.0 to 85.0 mol %.

8. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin contains an acetyl group in an amount of 0.1 to 20.0 mol %.

9. The epoxy resin composition according to claim 1, wherein the modified polyvinyl acetal resin is present in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the epoxy resin.

Description

DESCRIPTION OF EMBODIMENTS

[0177] The present invention is more specifically described in the following with reference to, but not limited to, examples.

Example 1

(Preparation of Modified Polyvinyl Acetal Resin)

[0178] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0179] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0180] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0181] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0182] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0183] An amount of 20 parts by weight of the obtained modified polyvinyl acetal resin, 100 parts by weight of an epoxy resin, 3 parts by weight of a curing agent, 2 parts by weight of a curing accelerator, and 10 parts by weight of an inorganic filler were mixed to prepare an epoxy resin composition.

[0184] The epoxy resin, curing agent, curing accelerator, and inorganic filler used are listed below.

[0185] Epoxy resin: Bisphenol A-type epoxy resin (jER 828 available from Mitsubishi Chemical Corporation, epoxy equivalent: 190, molecular weight: 370)

[0186] Propylene glycol diglycidyl ether (DENACOL EX-920 available from Nagase ChemteX Corporation, epoxy equivalent: 176, molecular weight: 350)

[0187] Curing agent: Dicyandiamide (DICY7 available from Mitsubishi Chemical Corporation)

[0188] Curing accelerator: Imidazole compound (jERCURE EMI24 available from Mitsubishi Chemical Corporation)

[0189] Inorganic filler: Calcium carbonate

Example 2

(Preparation of Modified Polyvinyl Acetal Resin)

[0190] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0191] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 25.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0192] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0193] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 25.0 mol %).

[0194] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0195] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 3

(Preparation of Modified Polyvinyl Acetal Resin)

[0196] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0197] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 10.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0198] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0199] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 10.0 mol %).

[0200] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by C-NMR.

[0201] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 4

(Preparation of Modified Polyvinyl Acetal Resin)

[0202] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0203] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 7.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0204] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0205] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 7.0 mol %).

[0206] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0207] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 5

(Preparation of Modified Polyvinyl Acetal Resin)

[0208] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0209] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-5) (in the formula (1-5), R.sup.8 represents a single bond and X.sup.8 represents a hydrogen atom, SP value of the constitutional unit: 14.1).

[0210] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0211] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-5) (amount: 5.5 mol %).

[0212] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0213] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 6

(Preparation of Modified Polyvinyl Acetal Resin)

[0214] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0215] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of an amino group-containing constitutional unit represented by the formula (2) (in the formula (2), R.sup.9 represents a single bond, SP value of the constitutional unit: 12.1).

[0216] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0217] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the amino group-containing constitutional unit represented by the formula (2) (amount: 5.5 mol %).

[0218] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0219] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 7

(Preparation of Modified Polyvinyl Acetal Resin)

[0220] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0221] The polyvinyl alcohol used had an average degree of polymerization of 200 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0222] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0223] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0224] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by C-NMR.

[0225] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 8

(Preparation of Modified Polyvinyl Acetal Resin)

[0226] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0227] The polyvinyl alcohol used had an average degree of polymerization of 450 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0228] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0229] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0230] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0231] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 9

(Preparation of Modified Polyvinyl Acetal Resin)

[0232] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0233] The polyvinyl alcohol used had an average degree of polymerization of 3,800 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0234] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0235] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0236] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0237] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 10

(Preparation of Modified Polyvinyl Acetal Resin)

[0238] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0239] The polyvinyl alcohol used had an average degree of polymerization of 5,000 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0240] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0241] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0242] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0243] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 11

(Preparation of Modified Polyvinyl Acetal Resin)

[0244] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 85 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0245] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0246] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0247] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0248] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0249] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 12

(Preparation of Modified Polyvinyl Acetal Resin)

[0250] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0251] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 14.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0252] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0253] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 14.5 mol %).

[0254] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0255] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 13

(Preparation of Modified Polyvinyl Acetal Resin)

[0256] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 85 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0257] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0258] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0259] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0260] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0261] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 14

(Preparation of Modified Polyvinyl Acetal Resin)

[0262] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0263] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 15.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0264] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0265] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 15.5 mol %).

[0266] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0267] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 15

(Preparation of Modified Polyvinyl Acetal Resin)

[0268] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 90 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0269] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0270] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0271] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0272] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0273] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 16

(Preparation of Modified Polyvinyl Acetal Resin)

[0274] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 85 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0275] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0276] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0277] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0278] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0279] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 17

(Preparation of Modified Polyvinyl Acetal Resin)

[0280] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0281] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 10.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0282] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0283] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 10.0 mol %).

[0284] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0285] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 18

(Preparation of Modified Polyvinyl Acetal Resin)

[0286] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0287] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 13.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0288] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0289] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 13.5 mol %).

[0290] Table 1 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0291] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 19

(Preparation of Modified Polyvinyl Acetal Resin)

[0292] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0293] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0294] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0295] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0296] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0297] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used and the amount of the modified polyvinyl acetal resin was changed as shown in Table 4.

Examples 20 to 22

[0298] Epoxy resin compositions were prepared as in Example 1, except that the modified polyvinyl acetal resin obtained in Example 19 was used and the amount of the modified polyvinyl acetal resin was changed as shown in Table 4.

Example 23

(Preparation of Modified Polyvinyl Acetal Resin)

[0299] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 60 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0300] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 20.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0301] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0302] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 20.0 mol %).

[0303] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0304] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used and the amount of the modified polyvinyl acetal resin was changed as shown in Table 4.

Example 24

(Preparation of Modified Polyvinyl Acetal Resin)

[0305] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 90 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0306] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.2 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0307] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0308] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.2 mol %).

[0309] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0310] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used and the amount of the modified polyvinyl acetal resin was changed as shown in Table 4.

Example 25

(Preparation of Modified Polyvinyl Acetal Resin)

[0311] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 70 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0312] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a sulfonic acid group-containing constitutional unit represented by the formula (3) (in the formula (3), R.sup.u represents a single bond and X.sup.9 represents a hydrogen atom, SP value of the constitutional unit: 20.2).

[0313] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0314] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the sulfonic acid group-containing constitutional unit represented by the formula (3) (amount: 5.1 mol %).

[0315] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0316] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 26

(Preparation of Modified Polyvinyl Acetal Resin)

[0317] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 70 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0318] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of an ethylene oxide group-containing constitutional unit represented by the formula (4) (in the formula (4), R.sup.11 represents a methylene group, X.sup.10 represents a hydrogen atom, and n represents 5, SP value of the constitutional unit: 10.9).

[0319] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0320] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the ethylene oxide group-containing constitutional unit represented by the formula (4) (amount: 5.5 mol %).

[0321] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0322] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 27

(Preparation of Modified Polyvinyl Acetal Resin)

[0323] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 120 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0324] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 6.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0325] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0326] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 6.5 mol %).

[0327] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0328] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 28

(Preparation of Modified Polyvinyl Acetal Resin)

[0329] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 50 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0330] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0331] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0332] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.5 mol %).

[0333] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0334] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 29

(Preparation of Modified Polyvinyl Acetal Resin)

[0335] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0336] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 3.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0337] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0338] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 3.5 mol %).

[0339] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0340] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 30

(Preparation of Modified Polyvinyl Acetal Resin)

[0341] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0342] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 33.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0343] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0344] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 33.5 mol %).

[0345] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0346] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 31

(Preparation of Modified Polyvinyl Acetal Resin)

[0347] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 120 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0348] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.1 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0349] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0350] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 5.1 mol %).

[0351] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0352] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 32

(Preparation of Modified Polyvinyl Acetal Resin)

[0353] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 70 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0354] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 32.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0355] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0356] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 32.0 mol %).

[0357] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0358] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Example 33

(Preparation of Modified Polyvinyl Acetal Resin)

[0359] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 120 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0360] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 3.5 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0361] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0362] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 3.5 mol %).

[0363] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0364] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Comparative Example 1

[0365] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight, 75 g of acetaldehyde, and 10 g of butyraldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0366] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %.

[0367] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0368] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0369] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Comparative Example 2

[0370] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 50 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0371] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 15.0 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0372] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0373] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 15.0 mol %).

[0374] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0375] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Comparative Example 3

[0376] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 120 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0377] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 0.4 mol % of a carboxyl group-containing constitutional unit represented by the formula (1-4) (in the formula (1-4), R.sup.6 represents a single bond, X.sup.6 represents a hydrogen atom, R.sup.7 represents a methylene group, and X.sup.7 represents a hydrogen atom, SP value of the constitutional unit: 15.1).

[0378] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0379] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the carboxyl group-containing constitutional unit represented by the formula (1-4) (amount: 0.4 mol %).

[0380] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

[0381] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

Comparative Example 4

[0382] An amount of 200 g of polyvinyl alcohol was added to 1,800 g of pure water, and stirred at 90° C. for about two hours to be dissolved. The solution was cooled to 40° C., and to the solution were added 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde. The acetalization was carried out by maintaining the solution temperature at 40° C. to precipitate a reaction product.

[0383] The polyvinyl alcohol used had an average degree of polymerization of 2,500 and a degree of saponification of 97.9 mol %, and contained 5.5 mol % of a Cert-butyl group-containing constitutional unit represented by the following formula (6) (in the formula (6), R.sup.13 represents an ethylene group, SP value of the constitutional unit: 8.1).

[0384] Then, the reaction solution was held to maintain the temperature at 40° C. for three hours, thereby completing the reaction. The resulting solution was subjected to neutralization, washing with water, and drying by normal methods, whereby a modified polyvinyl acetal resin powder was obtained.

[0385] The obtained modified polyvinyl acetal resin was dissolved in dimethylsulfoxide (DMSO-D.sub.6), and analyzed by .sup.13C-NMR (nuclear magnetic resonance spectrum) to confirm the presence of the tert-butyl group-containing constitutional unit represented by the following formula (6) (amount: 5.5 mol %).

[0386] Table 2 shows the acetal group content, the acetyl group content, and the hydroxyl group content measured by .sup.13C-NMR.

##STR00006##

[0387] An epoxy resin composition was prepared as in Example 1, except that the obtained modified polyvinyl acetal resin was used.

TABLE-US-00001 TABLE 1 Polyvinyl acetal resin Amount of Hydroxyl Structure SP value modified group of of Hydro- Average group- content + modified modified philic degree Acetal Acetyl Hydroxyl containing Hydrogen- Type group- group- unit/ of group group group constitutional bonding of containing containing Hydro- polymer- content content content unit group content modified constitutional constitutional phobic ization (mol %) (mol %) (mol %) (mol %) (mol %) group unit unit unit Example 1 2500 67.8 2.1 25.0 5.1 30.1 Carboxyl (1-4) 15.1 0.43 group Example 2 2500 47.9 2.1 25.0 25.0 50.0 Carboxyl (1-4) 15.1 1.00 group Example 3 2500 62.9 2.1 25.0 10.0 35.0 Carboxyl (1-4) 15.1 0.54 group Example 4 2500 42.9 2.1 48.0 7.0 55.0 Carboxyl (1-4) 15.1 1.22 group Example 5 2500 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-5) 14.1 0.44 group Example 6 2500 72.9 2.1 25.0 5.5 30.5 Amino (2) 12.1 0.41 group Example 7 200 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 8 450 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 9 3800 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 10 5000 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 11 2500 71.3 2.1 21.5 5.1 26.6 Carboxyl (1-4) 15.1 0.36 group Example 12 2500 38.9 2.1 44.5 14.5 59.0 Carboxyl (1-4) 15.1 1.44 group Example 13 2500 73.8 2.1 19.0 5.1 24.1 Carboxyl (1-4) 15.1 0.32 group Example 14 2500 36.9 2.1 45.5 15.5 61.0 Carboxyl (1-4) 15.1 1.56 group Example 15 2500 74.8 2.1 18.0 5.1 23.1 Carboxyl (1-4) 15.1 0.30 group Example 16 2500 70.8 2.1 22.0 5.1 27.1 Carboxyl (1-4) 15.1 0.37 group Example 17 2500 39.9 2.1 48.0 10.0 58.0 Carboxyl (1-4) 15.1 1.38 group Example 18 2500 36.4 2.1 48.0 13.5 61.5 Carboxyl (1-4) 15.1 1.60 group

TABLE-US-00002 TABLE 2 Polyvinyl acetal resin Amount Hydrox- SP of yl Structure value mod- group of of ified content + modified modified group- Hydro- group- group- Hydro- containing gen- con- con- philic Average Acetal Acetyl Hydroxyl consti- bonding Type taining taining unit/ degree of group group group tutional group of consti- consti- Hydro- polymer- content content content unit content modified tutional tutional phobic ization (mol %) (mol %) (mol %) (mol %) (mol %) group unit unit unit Example 19 2500 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 20 2500 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 21 2500 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 22 2500 67.4 2.1 25.0 5.5 30.5 Carboxyl (1-4) 15.1 0.44 group Example 23 2500 32.9 2.1 45.0 20.0 65.0 Carboxyl (1-4) 15.1 1.86 group Example 24 2500 74.7 2.1 18.0 5.2 23.2 Carboxyl (1-4) 15.1 0.30 group Example 25 2500 67.3 2.1 25.5 5.1 30.6 Sulfonic (3) 20.2 0.44 acid group Example 26 2500 66.9 2.1 25.5 5.5 31.0 Ethylene (4) 10.9 0.34 oxide group Example 27 2500 82.5 2.1 8.9 6.5 15.4 Carboxyl (1-4) 15.1 0.18 group Example 28 2500 37.2 2.1 55.2 5.5 60.7 Carboxyl (1-4) 15.1 1.54 group Example 29 2500 69.4 2.1 25.0 3.5 28.5 Carboxyl (1-4) 15.1 0.40 group Example 30 2500 39.4 2.1 25.0 33.5 58.5 Carboxyl (1-4) 15.1 1.41 group Example 31 2500 83.9 2.1 8.9 5.1 14.0 Carboxyl (1-4) 15.1 0.16 group Example 32 2500 30.9 2.1 35.0 32.0 67.0 Carboxyl (1-4) 15.1 2.03 group Example 33 2500 85.5 2.1 8.9 3.5 12.4 Carboxyl (1-4) 15.1 0.14 group Comparative 1 2500 72.9 2.1 25.0 — 25.0 — — — 0.33 Example Comparative 2 2500 17.9 2.1 65.0 15.0 80.0 Carboxyl (1-4) 15.1 4.00 Example group Comparative 3 2500 67.9 2.1 8.0 0.4 8.4 Carboxyl (1-4) 15.1 0.12 Example group Comparative 4 2500 67.4 2.1 25.0 5.5 25.0 tert-Butyl (6) 8.1 0.33 Example group

TABLE-US-00003 TABLE 3 Epoxy resin composition (Number Number of of hydroxyl hydrogen- Epoxy resin groups + Number of bonding Polyvinyl (parts by weight) Curing hydrogen-bonding groups/ acetal Bisphenol Propylene accelerator Inorganic filler groups)/ Number resin A-type glycol Curing agent (parts by weight) (parts by weight) Number of of (parts by epoxy diglycidyl (parts by weight) Imidazole Calcium epoxy epoxy weight) resin ether Dicyandiamide compound carbonate groups groups Example 1 20 80 20 3 2 10 0.226 0.066 Example 2 20 80 20 3 2 10 0.386 0.257 Example 3 20 80 20 3 2 10 0.273 0.121 Example 4 20 80 20 3 2 10 0.410 0.093 Example 5 20 80 20 3 2 10 0.188 0.019 Example 6 20 80 20 3 2 10 0.201 0.036 Example 7 20 80 20 3 2 10 0.230 0.070 Example 8 20 80 20 3 2 10 0.230 0.070 Example 9 20 80 20 3 2 10 0.230 0.070 Example 10 20 80 20 3 2 10 0.230 0.070 Example 11 20 80 20 3 2 10 0.202 0.065 Example 12 20 80 20 3 2 10 0.440 0.174 Example 13 20 80 20 3 2 10 0.185 0.065 Example 14 20 80 20 3 2 10 0.454 0.184 Example 15 20 80 20 3 2 10 0.179 0.065 Example 16 20 80 20 3 2 10 0.206 0.065 Example 17 20 80 20 3 2 10 0.433 0.127 Example 18 20 80 20 3 2 10 0.458 0.165

TABLE-US-00004 TABLE 4 Epoxy resin composition (Number of hydroxyl Poly- Curing groups + Number of vinyl Epoxy resin accelerator Inorganic hydrogen- acetal (parts by weight) Curing agent (parts filler bonding Number of resin Bisphenol A- Propylene (parts by by (parts by groups)/ hydrogen- (Parts type glycol weight) weight) weight) Number of bonding by epoxy diglycidyl Dicyan- Imidazole Calcium epoxy groups/Number of weight) resin ether diamide compound carbonate groups epoxy groups Example 19 3 80 20 3 2 10 0.035 0.011 Example 20 6 80 20 3 2 10 0.069 0.021 Example 21 28 80 20 3 2 10 0.323 0.099 Example 22 40 80 20 3 2 10 0.461 0.141 Example 23 44 80 20 3 2 10 1.053 0.496 Example 24 2 80 20 3 2 10 0.018 0.007 Example 25 20 80 20 3 2 10 0.201 0.033 Example 26 20 80 20 3 2 10 0.174 0.031 Example 27 20 80 20 3 2 10 0.134 0.079 Example 28 20 80 20 3 2 10 0.454 0.075 Example 29 20 80 20 3 2 10 0.210 0.046 Example 30 20 80 20 3 2 10 0.436 0.318 Example 31 20 80 20 3 2 10 0.119 0.063 Example 32 20 80 20 3 2 10 0.484 0.313 Example 33 20 80 20 3 2 10 0.101 0.044 Comparative 1 20 80 20 3 2 10 0.172 — Example Comparative 2 20 80 20 3 2 10 0.591 0.186 Example Comparative 3 20 80 20 3 2 10 0.074 0.007 Example Comparative 4 30 80 20 3 2 10 0.278 — Example

<Evaluation>

[0388] The following evaluations were performed on the polyvinyl acetal resins and epoxy resin compositions obtained in the examples and comparative examples. Tables 5 and 6 show the results.

(1) Equilibrium Moisture Absorption

[0389] The polyvinyl acetal resins obtained in the examples and comparative examples were each dried in a vacuum oven to a moisture content of 0.5% or lower, and exposed to an environment of 40° C. and 90% RH for seven days. Based on the weight change of the resulting polyvinyl acetal resin taken as the amount of absorbed moisture, the moisture absorption rate was calculated. The obtained moisture absorption rate was taken as the equilibrium moisture absorption (% by weight). It is to be noted that the equilibrium moisture absorption is different from the conventional moisture content.

(2) Speed of Moisture Absorption

[0390] The obtained polyvinyl acetal resins were each dried in a vacuum oven to a moisture content of 0.5% or lower, and exposed to an environment of 40° C. and 90% RH for seven days. The speed of moisture absorption (g/g/h) was calculated by dividing the amount (g/g) of moisture absorbed by 1 g of the polyvinyl acetal resin when the equilibrium moisture absorption was achieved by the time (h) to reach the equilibrium moisture absorption.

(3) 5% Resin Viscosity

[0391] The obtained polyvinyl acetal resins were each dissolved in a solvent mixture containing ethanol and toluene at a ratio of 1:1 to prepare a 5% by weight solution. The viscosity of the obtained solution was measured with a B-type viscometer at a solution temperature of 20° C.

(4) Elastic Modulus

[0392] The polyvinyl acetal resins obtained in the examples and comparative examples were each dissolved in a solvent mixture containing ethanol and toluene at a ratio of 1:1 at a concentration of 30% by weight to prepare a polyvinyl acetal resin solution.

[0393] The obtained polyvinyl acetal resin solution was applied to a 100 μm-thick polyethylene terephthalate film to a dry thickness of 20 μm. The resulting polyvinyl acetal film was peeled from the polyethylene terephthalate film and cut into a 1×5 cm piece. Using the obtained film piece, the elastic modulus (MPa) was measured with an autograph (AGS-J available from Shimadzu Corporation) at 25° C. and a tensile speed of 30 mm/min.

(5) Gel Fraction

[0394] The obtained epoxy resin compositions were each applied to aluminum foil to a dry thickness of 100 μm. The applied composition was heated at 160° C. for 30 minutes to be cured. To the resulting epoxy resin sheet (about 0.1 g) (w1) was added 40 g of a solvent mixture containing toluene and ethanol at a weight ratio of 1:1, followed by stirring for 24 hours. The resulting solution was subjected to solid-liquid separation using a 200-mesh stainless steel sieve the mass (w2) of which had been weighed in advance. The stainless-steel sieve was taken out, and dried in vacuum at 100° C. for one hour, followed by measurement of the mass (w3) thereof. The gel fraction was calculated by the following equation.

Gel fraction (% by weight)={(w3−w2)/w1}×100

(6) Storage Stability

[0395] The obtained epoxy resin compositions were each subjected to measurement of the viscosity right after the preparation and after one month from the preparation using a B-type viscometer to determine the change rate of the viscosity. The evaluation was performed in accordance with the following criteria.

∘ (Good): lower than 10%
Δ (Fair): 10% or higher but lower than 25%
x (Poor): 25% or higher

(7) Tensile Elongation

[0396] The obtained epoxy resin compositions were each poured into a mold and heated at 160° C. for 30 minutes to be cured. Thus, a dumbbell-shaped specimen was provided. Using the obtained dumbbell-shaped specimen, a tensile test in conformity with JIS K7161 was performed at 25° C. and a tensile speed of 5 mm/min to determine the tensile elongation (%).

(8) Shear Adhesion

[0397] The obtained epoxy resin compositions were each applied to a SPCC steel plate to a contact surface area of 300 mm.sup.2 and a thickness after curing of 100 μm and another SPCC steel plate was attached thereto. Thus, a test specimen was provided. The resulting test specimen was heated at 160° C. for 30 minutes for curing, and subjected to measurement of the shear adhesion (MPa) by a method in conformity with JIS K 6850 at a measurement temperature of 25° C. and a tensile speed of 5 ram/min.

(9) Peel Adhesion

[0398] The obtained epoxy resin compositions were each applied to a SPCC steel plate to a thickness after curing of 200 μm and another SPCC steel plate was attached thereto. Thus, a specimen for T-peel test was provided. The obtained specimen was heated at 160° C. for 30 minutes for curing, and subjected to measurement of the peel adhesion (N/25 mm) by a method in conformity with JIS K 6854 at a measurement temperature of 25° C. and a tensile speed of 100 mm/min.

(10) Moisture Resistance (Peel Adhesion and Adhesive Retention in High-Temperature, High-Humidity Environment)

[0399] A specimen for T-peel test was provided as in (9) Peel adhesion. The obtained specimen was exposed to an environment of a temperature of 85° C. and a humidity of 85% RH for seven days. Then, the peel adhesion (N/25 mm) in a high-temperature, high-humidity environment was measured as in (9) Peel adhesive force. The proportion of the peel adhesion in a high-temperature, high-humidity environment to the (9) Peel adhesion was calculated for evaluation of the adhesive retention (%).

(11) Impact Resistance (Charpy Impact Value)

[0400] The obtained epoxy resin compositions were each poured into a mold and heated at 160° C. for 30 minutes, thereby preparing a specimen for Charpy impact test. The obtained specimen was subjected to a Charpy impact test by a method in conformity with JIS K 7111 using a digital impact tester DG-UB type (product of Toyo Seiki Seisakusho, Ltd.). Based on the measured Charpy impact value (kJ/m.sup.2) upon breakage of the resin cured product, the impact resistance was evaluated.

TABLE-US-00005 TABLE 5 Evaluation Epoxy resin composition Moisture resistance Polyvinyl Peel acetal adhesion resin in Equi- Speed high- Impact librium of temperature, resistance moisture moisture 5% Tensile Shear Peel high- Ad- Charpy absorp- absorp- resin Elastic elon- ad- ad- humidity hesive impact tion tion viscosity modulus Gel fraction Storage gation hesion hesion environment retention value (wt %) (g/g/h) (mPa .Math. s) (Mpa) (wt %) stability (%) (Mpa) (N/25 mm) (N/25 mm) (%) (kJ/m.sup.2) Example 1 6.6 0.0034 222 1050 99.6 Good 8.7 33.4 125 108 86.4 3.5 Example 2 14.3 0.0074 220 1550 99.8 Good 11.5 35.4 166 159 95.8 6.7 Example 3 10.2 0.0053 220 1320 99.7 Good 12.1 36.1 158 149 94.3 3.6 Example 4 18.7 0.0097 224 1700 98.8 Fair 6.4 38.9 145 124 85.5 3.5 Example 5 5.8 0.0030 221 1080 99.0 Good 9.1 35.5 130 108 83.1 4.9 Example 6 5.1 0.0027 223 990 95.8 Fair 6.2 30.3 108 88 81.5 3.6 Example 7 7.1 0.0037 12 1200 99.5 Good 7.1 32.5 128 117 91.4 4.2 Example 8 7.7 0.0040 41 1180 99.1 Good 7.6 33.3 122 113 92.6 4.2 Example 9 7.7 0.0040 390 990 99.4 Good 9.4 34.2 125 116 92.8 5.1 Example 10 7.5 0.0039 445 970 99.4 Good 10 31.9 120 111 92.5 5.4 Example 11 7.2 0.0038 225 820 99.7 Good 8.4 31.9 118 108 91.5 4.7 Example 12 14.8 0.0077 230 1620 96.5 Fair 5.9 38.5 141 136 96.5 3.7 Example 13 6.1 0.0032 210 790 99.1 Good 8.6 32.1 112 96 85.7 4.9 Example 14 17.5 0.0091 232 1680 97.2 Fair 5.6 37.9 136 119 87.5 3.5 Example 15 5.5 0.0029 208 780 99.6 Good 8.6 31.5 111 91 82.0 3.7 Example 16 7.4 0.0039 212 880 99.4 Good 8.3 31.9 120 111 92.5 3.6 Example 17 14.1 0.0073 232 1720 99.6 Fair 5.7 38.3 138 132 95.7 5.4 Example 18 18.8 0.0098 248 1720 99.1 Fair 5.6 37.7 136 117 86.0 5.6

TABLE-US-00006 TABLE 6 Evaluation Expoxy resin composition Moisture resistance Peel adhesion in high- Polyvinyl acetal resin temper- Equi- Speed ature, librium of 5% Ten- high- Impact water water resin sile humidity Ad- resistance absorp- absorp- vis- Elastic Gel elon- Shear Peel environ- hesive Charpy tion tion cosity modulus fraction Storage gation adhesion adhesion ment retention impact (wt %) (g/g/h) (mPa .Math. s) (Mpa) (wt %) stability (%) (Mpa) (N/25 mm) (N/25 mm) (%) (kJ/m.sup.2) Example 19 6.8 0.0035 221 1080 99.5 Good 4.3 25.6 82 70 85.4 2.5 Example 20 6.8 0.0035 221 1080 99.6 Good 4.7 27.0 101 85 84.2 2.8 Example 21 6.8 0.0035 221 1080 98.6 Fair 5.1 39.5 170 151 88.8 5.6 Example 22 6.8 0.0035 221 1080 90.5 Fair 4.1 35.1 125 107 85.6 5.5 Example 23 19.2 0.0100 251 1750 91.7 Fair 5.0 34.7 132 113 85.6 4.6 Example 24 5.7 0.0030 209 780 99.5 Good 8.8 31.8 77 64 83.1 3.8 Example 25 18.8 0.0135 214 1340 90.2 Fair 5.1 24.8 110 99 90.2 3.2 Example 26 5.1 0.0025 245 620 91.0 Fair 9.2 23.2 110 73 66.0 5.2 Example 27 5.4 0.0022 205 760 98.9 Good 7.1 31.8 142 102 72.0 5.2 Example 28 18.6 0.0051 238 1480 98.2 Fair 8.0 32.0 134 114 85.1 4.0 Example 29 5.2 0.0018 198 720 97.8 Good 5.8 30.1 121 96 79.6 3.4 Example 30 19.5 0.0130 281 1840 99.7 Fair 7.4 27.5 123 112 91.2 2.4 Example 31 5.2 0.0020 195 750 98.4 Good 6.5 26.2 138 97 70.6 4.5 Example 32 19.8 0.0160 275 1920 99.6 Fair 7.1 26.8 117 99 84.2 2.7 Example 33 5.0 0.0016 190 700 96.8 Good 5.0 25.0 72 49 68.7 3.1 Comparative 1 4.3 0.0016 217 660 88.9 Good 5.5 24.5 54 26 48.1 2.2 Example Comparative 2 24.8 0.0172 293 2250 92.2 Poor 4.1 30.7 100 69 57.5 2.6 Example Comparative 3 3.2 0.0017 186 520 99.5 Good 3.9 19.8 108 45 41.7 2.1 Example Comparative 4 2.4 0.0013 260 620 91.3 Poor 5.6 20.0 61 31 50.8 3.0 Example

INDUSTRIAL APPLICABILITY

[0401] The present invention can provide an epoxy resin composition capable of exhibiting high moisture resistance and reducing reduction in adhesion at high temperature and high humidity.