ADHESIVE

Abstract

The present invention aims to provide an adhesive that has excellent adhesiveness to both organic materials (particularly, polycarbonate, acrylic, and nylon) and inorganic materials, is capable of exhibiting excellent transparency and toughness, and also has excellent handleability. The present invention relates to an adhesive containing: a modified polyvinyl acetal having an imine structure; a reactive diluent; and a polymerization initiator.

Claims

1. An adhesive comprising: a modified polyvinyl acetal having an inline structure; a reactive diluent; and a polymerization initiator.

2. The adhesive according to claim 1, wherein the reactive diluent is a (meth)acrylic reactive diluent or an epoxy reactive diluent.

3. The adhesive according to claim 1, wherein the amount of the reactive diluent relative to 100 parts by weight of the modified polyvinyl acetal having an imine structure is 60 to 5,000 parts by weight.

4. The adhesive according to claim 2, wherein the amount of the reactive diluent relative to 100 parts by weight of the modified polyvinyl acetal having an imine structure is 60 to 5,000 parts by weight.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0080] FIG. 1 is a schematic view illustrating a specimen used for testing the tensile lap-shear strength of adhesive in examples.

DESCRIPTION OF EMBODIMENTS

[0081] Embodiments of the present invention will be specifically described in the following with reference to, but not limited to, examples.

<Preparation of Modified Polyvinyl Butyral>

(1) Preparation of Modified Polyvinyl Butyral 1

[0082] Polyvinyl alcohol (240 g) with a degree of polymerization of 600, a degree of saponification of 99 mol %, and 1.7 mol % of a constitutional unit having an amino group (NH.sub.2) represented by Formula (3) above was added to 1,800 g of pure water. The mixture was stirred at 90 C. for about two hours to dissolve the polyvinyl alcohol. The solution was cooled to 40 C., followed by the addition of 170 g of 35% by weight hydrochloric acid and 275 g of n-butyraldehyde. The solution temperature was maintained at 40 C. to allow acetalization reaction to proceed, whereby the reaction product was precipitated.

[0083] Thereafter, the solution temperature was maintained at 40 C. for three hours to complete the reaction. Neutralization, water washing, and drying were conducted by conventional methods to give powder of a modified polyvinyl butyral 1.

[0084] The obtained modified polyvinyl butyral 1 was dissolved into dimethyl sulfoxide (DMSO-d.sub.6) and analyzed by .sup.13C-NMR (nuclear magnetic resonance) spectroscopy. The analysis showed that the degree of butyralization was 77.5 mol %, the hydroxy group content was 20.0 mol %, the acetyl group content was 0.4 mol %, and the amount of the constitutional unit having an imine structure represented by Formula (5) below (R.sup.3 is hydrogen and R.sup.4 is an n-butyl group) was 1.7 mol %.

##STR00004##

(2) Preparation of Modified Polyvinyl Butyral 2

[0085] Polyvinyl alcohol (250 g) with a degree of polymerization of 600, a degree of saponification of 99 mol %, and 8.3 mol % of a constitutional unit having an amino group (NH.sub.2) represented by Formula (3) above was added to 1,800 g of pure water. The mixture was stirred at 90 C. for about two hours to dissolve the polyvinyl alcohol. The solution was cooled to 40 C., followed by the addition of 170 g of 35% by weight hydrochloric acid and 150 g of n-butyraldehyde. The solution temperature was maintained at 40 C. to allow acetalization reaction to proceed, whereby the reaction product was precipitated.

[0086] Thereafter, the solution temperature was maintained at 40 C. for three hours to complete the reaction. Neutralization, water washing, and drying were conducted by conventional methods to give powder of a modified polyvinyl butyral 2.

[0087] The obtained modified polyvinyl butyral 2 was dissolved into dimethylsulfoxide (DMSO-d.sub.6) and analyzed by .sup.13C-NMR (nuclear magnetic resonance) spectroscopy. The analysis showed that the degree of butyralization was 70.0 mol %, the hydroxy group content was 20.9 mol %, the acetyl group content was 0.3 mol %, and the amount of the constitutional unit having an imine structure represented by Formula (5) above (R.sup.3 is hydrogen and R.sup.4 is an n-butyl group) was 8.3 mol %.

(3) Preparation of Modified Polyvinyl Butyral 3

[0088] Polyvinyl alcohol (250 g) with a degree of polymerization of 200, a degree of saponification of 99 mol %, and 1.7 mol % of a constitutional unit having an amino group (NH.sub.2) represented by Formula (3) above was added to 1,800 g of pure water. The mixture was stirred at 90 C. for about two hours to dissolve the polyvinyl alcohol. The solution was cooled to 40 C., followed by the addition of 170 g of 35% by weight hydrochloric acid and 120 g of n-butyraldehyde. The solution temperature was maintained at 40 C. to allow acetalization reaction to proceed, whereby the reaction product was precipitated.

[0089] Thereafter, the solution temperature was maintained at 40 C. for three hours to complete the reaction. Neutralization, water washing, and drying were conducted by conventional methods to give powder of a modified polyvinyl butyral 3.

[0090] The obtained modified polyvinyl butyral 3 was dissolved into dimethylsulfoxide (DMSO-d.sub.6) and analyzed by .sup.13C-NMR (nuclear magnetic resonance) spectroscopy. The analysis showed that the degree of butyralization was 77.5 mol %, the hydroxy group content was 20.0 mol %, the acetyl group content was 0.4 mol %, and the amount of the constitutional unit having an imine structure represented by Formula (5) above (R.sup.3 is hydrogen and R.sup.4 is an n-butyl group) was 1.7 mol %.

(4) Preparation of Modified Polyvinyl Butyral 4

[0091] Polyvinyl alcohol (240 g) with a degree of polymerization of 1,200, a degree of saponification of 99 mol %, and 1.7 mol % of a constitutional unit having an amino group (NH.sub.2) represented by Formula (3) above was added to 1,800 g of pure water. The mixture was stirred at 90 C. for about two hours to dissolve the polyvinyl alcohol. The solution was cooled to 40 C., followed by the addition of 170 g of 35% by weight hydrochloric acid and 275 g of n-butyraldehyde. The solution temperature was maintained at 40 C. to allow acetalization reaction to proceed, whereby the reaction product was precipitated.

[0092] Thereafter, the solution temperature was maintained at 40 C. for three hours to complete the reaction. Neutralization, water washing, and drying were conducted by conventional methods to give powder of a modified polyvinyl butyral 4.

[0093] The obtained modified polyvinyl butyral 4 was dissolved into dimethylsulfoxide (DMSO-d.sub.6) and analyzed by .sup.13C-NMR (nuclear magnetic resonance) spectroscopy. The analysis showed that the degree of butyralization was 77.5 mol %, the hydroxy group content was 20.0 mol %, the acetyl group content was 0.4 mol %, and the amount of the constitutional unit having an imine structure represented by Formula (5) above (R.sup.3 is hydrogen and R.sup.4 is an n-butyl group) was 1.7 mol %.

<Preparation of Polyvinyl Butyral>

[0094] Polyvinyl alcohol (250 g) with a degree of polymerization of 650 and a degree of saponification of 99 mol % was added to 1,800 g of pure water. The mixture was stirred at 90 C. for about two hours to dissolve the polyvinyl alcohol. The solution was cooled to 40 C., followed by the addition of 170 g of 35% by weight hydrochloric acid and 275 g of n-butyraldehyde. The solution temperature was maintained at 40 C. to allow acetalization reaction to proceed, whereby the reaction product was precipitated.

[0095] Thereafter, the solution temperature was maintained at 40 C. for three hours to complete the reaction. Neutralization, water washing, and drying were conducted by conventional methods to give powder of a polyvinyl butyral.

[0096] The obtained polyvinyl butyral was dissolved into dimethylsulfoxide (DMSO-d.sub.6) and analyzed by .sup.13C-NMR (nuclear magnetic resonance) spectroscopy. The analysis showed that the degree of acetalization was 65.0 mol %, the hydroxy group content was 34.0 mol %, and the acetyl group content was 1.0 mol %.

Example 1

[0097] To 100 parts by weight of the modified polyvinyl butyral 2 was added 100 parts by weight of a (meth)acrylic reactive diluent (30% by weight of methyl methacrylate, 40% by weight of ethyl acrylate, and 30% by weight of 2-hydroxyethyl acrylate) as a reactive diluent, followed by sufficient stirring and mixing. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. The mixed composition was sufficiently blended with a perester compound (NOF Corporation, Perbutyl 355) as a thermal polymerization initiator in an amount of 5.0 parts by weight relative to 100 parts by weight of the reactive diluent, whereby an adhesive was obtained. The obtained adhesive was in a liquid (sol) state at room temperature.

Example 2, Comparative Example 1

[0098] An adhesive was obtained in the same manner as in Example 1 except that the type of the modified polyvinyl butyral, the amount of the reactive diluent, and the like were as shown in Table 1. The obtained adhesive was in a liquid (sol) state at room temperature.

Example 3

[0099] To 100 parts by weight of the modified polyvinyl butyral 2 was added 100 parts by weight of a bisphenol A epoxy monomer (Mitsubishi Chemical Corporation, jER828) as a reactive diluent, followed by heating and dissolving. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. This mixed composition was cooled to 23 C., followed by the addition of 25 parts by weight of 2,4-diamino-6-[2-undecylimidazolyl-(1)]-ethyl-s-triazine (Shikoku Chemicals Corporation, C11Z-A) as a thermal polymerization initiator, and further followed by sufficient stirring and mixing to give an adhesive. The obtained adhesive was in a liquid (sol) state at room temperature.

Example 4, Comparative Example 2

[0100] An adhesive was obtained in the same manner as in Example 3 except that the type of the modified polyvinyl butyral, the amount of the reactive diluent, and the like were as shown in Table 1. The obtained adhesive was in a liquid (sol) state at room temperature.

(Evaluation)

[0101] The adhesives obtained in the examples and comparative examples were evaluated by the following method.

[0102] The results are shown in Table 1.

(Evaluation of Adhesiveness to Various Materials)

[0103] Specimens as shown in FIG. 1 were prepared in conformity with the method for testing tensile lap-shear strength of adhesive specified in JIS K 6850. The substrates as the evaluation subjects were glass, aluminum, SUS, polycarbonate (PC), acrylic, and nylon. The adhesive was applied to bond the substrates and heated in an oven at 130 C. for 30 minutes to be cured. Thereafter, the tensile lap-shear strength was measured using a Tensilon universal material tester (A & D Company, Limited, RTC-1350A).

TABLE-US-00001 TABLE 1 Reactive diluent (Modified) polyvinyl acetal (parts by weight) Acetyl Hydroxy Imine (Meth) Degree of group group modification acrylic Epoxy Degree of acetalization content content content reactive reactive polymerization (mol %) (mol %) (mol %) (mol %) diluent diluent Example 1 600 70.0 0.3 20.9 8.3 100 Example 2 600 77.5 0.4 20.0 1.7 100 Comparative 650 65.0 1.0 34.0 100 Example 1 Example 3 600 70.0 0.3 20.9 8.3 100 Example 4 600 77.5 0.4 20.0 1.7 100 Comparative 650 65.0 1.0 34.0 100 Example 2 Polymerization initiator (parts by weight) Perester Imidazole polymerization polymerization Tensile lap-shear strength (MPa) initiator initiator Glass Aluminum SUS PC Acrylic Nylon Example 1 5.0 51.2 45.3 40.3 7.7 8.7 10.2 Example 2 5.0 43.0 38.0 35.4 7.6 8.2 9.1 Comparative 5.0 13.6 15.0 13.4 2.5 1.5 1.8 Example 1 Example 3 25 53.0 35.7 27.3 3.4 4.0 13.3 Example 4 25 48.0 33.2 27.2 3.3 3.9 13.2 Comparative 25 13.6 8.6 7.1 2.8 1.0 3.4 Example 2

[0104] Table 1 shows that the adhesives of Examples 1 to 4, each prepared using a modified polyvinyl butyral having an imine structure, exhibit excellent adhesiveness both when the adherends are inorganic materials (i.e., glass, aluminum, and SUS) and when the adherends are organic materials (i.e., polycarbonate (PC), acrylic, and nylon) as compared with the adhesives of Comparative Examples 1 and 2, each prepared from polyvinyl butyral. This indicates that the adhesives of Examples 1 to 4 are usable for a wide range of adherends. Table 1 also shows that in the case where the modified polyvinyl acetal having an imine structure contains a large amount a constitutional unit having an imine structure, the adhesive tends to have high adhesiveness particularly when the adherends are inorganic materials.

Example 5

[0105] To 100 parts by weight of the modified polyvinyl butyral 3 was added 100 parts by weight of a (meth)acrylic reactive diluent (30% by weight of methyl methacrylate, 40% by weight of ethyl acrylate, and 30% by weight of 2-hydroxyethyl acrylate) as a reactive diluent, followed by sufficient stirring and mixing. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. The mixed composition was sufficiently blended with a perester compound (NOF Corporation, Perbutyl 355) as a thermal polymerization initiator in an amount of 5.0 parts by weight relative to 100 parts by weight of the reactive diluent, whereby an adhesive was obtained. The obtained adhesive was in a liquid (sol) state at room temperature.

Examples 6 and 7

[0106] An adhesive was obtained in the same manner as in Example 5 except that the type of the modified polyvinyl butyral was as shown in Table 2. The obtained adhesive was in a liquid (sol) state at room temperature.

Example 8

[0107] To 100 parts by weight of the modified polyvinyl butyral 3 was added 100 parts by weight of a bisphenol A epoxy monomer (Mitsubishi Chemical Corporation, jER828) as a reactive diluent, followed by heating and dissolving. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. This mixed composition was cooled to 23 C., followed by the addition of 25 parts by weight of 2,4-diamino-6-[2-undecylimidazolyl-(1)]-ethyl-s-triazine (Shikoku Chemicals Corporation, C11Z-A) as a thermal polymerization initiator, and further followed by sufficient stirring and mixing to give an adhesive. The obtained adhesive was in a liquid (sol) state at room temperature.

Examples 9 and 10

[0108] An adhesive was obtained in the same manner as in Example 8 except that the type of the modified polyvinyl butyral was as shown in Table 2. The obtained adhesive was in a liquid (sol) state at room temperature.

(Evaluation)

[0109] The adhesives obtained in the examples and comparative examples were evaluated concerning the adhesiveness to various materials by the above method.

[0110] The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Reactive diluent (Modified) polyvinyl acetal (parts by weight) Acetyl Hydroxy Imine (Meth) Degree of group group modification acrylic Epoxy Degree of acetalization content content content reactive reactive polymerization (mol %) (mol %) (mol %) (mol %) diluent diluent Example 5 200 77.5 0.4 20.0 1.7 100 Example 6 600 77.5 0.4 20.0 1.7 100 Example 7 1200 77.5 0.4 20.0 1.7 100 Example 8 200 77.5 0.4 20.0 1.7 100 Example 9 600 77.5 0.4 20.0 1.7 100 Example 10 1200 77.5 0.4 20.0 1.7 100 Polymerization initiator (parts by weight) Perester Imidazole polymerization polymerization Tensile lap-shear strength (MPa) initiator initiator Glass Aluminum SUS PC Acrylic Nylon Example 5 5.0 42.0 34.0 32.1 7.5 8.0 8.9 Example 6 5.0 43.0 38.0 35.4 7.6 8.2 9.1 Example 7 5.0 44.1 38.2 35.5 7.7 8.2 9.1 Example 8 25 47.7 33.1 27.0 3.3 3.9 13.2 Example 9 25 48.0 33.2 27.2 3.3 3.9 13.2 Example 10 25 48.0 33.3 27.2 3.4 4.0 13.3

[0111] Table 2 indicates that adhesives within the scope of these examples can exhibit excellent adhesiveness both when the adherends are inorganic materials and when the adherends are organic materials regardless of the degree of polymerization of the modified polyvinyl butyral having an imine structure.

Example 11

[0112] To 100 parts by weight of the modified polyvinyl butyral 1 was added 60 parts by weight of a (meth)acrylic reactive diluent (30% by weight of methyl methacrylate, 40% by weight of ethyl acrylate, and 30% by weight of 2-hydroxyethyl acrylate) as a reactive diluent, followed by sufficient stirring and mixing. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. The mixed composition was sufficiently blended with a perester compound (NOF Corporation, Perbutyl 355) as a thermal polymerization initiator in an amount of 3.0 parts by weight, whereby an adhesive was obtained. The obtained adhesive was in a liquid (sol) state at room temperature.

Examples 12 to 28

[0113] An adhesive was obtained in the same manner as in Example 11 except that the type of the modified polyvinyl butyral, the amount of the reactive diluent, and the like were as shown in Table 3. The obtained adhesive was in a liquid (sol) state at room temperature.

Example 29

[0114] To 100 parts by weight of the modified polyvinyl butyral 1 was added 60 parts by weight of a bisphenol A epoxy monomer (Mitsubishi Chemical Corporation, jER828) as a reactive diluent, followed by heating and dissolving. Vacuum deaeration treatment was then performed using a vacuum-type deaeration device (Thinky Corporation, AV-310) at 1,200 rpm and 1.0 kPa for three minutes to give a mixed composition. This mixed composition was cooled to 23 C., followed by the addition of 15 parts by weight of 2,4-diamino-6-[2-undecylimidazolyl-(1)]-ethyl-s-triazine (Shikoku Chemicals Corporation, C11Z-A) as a thermal polymerization initiator, and further followed by sufficient stirring and mixing to give an adhesive. The obtained adhesive was in a liquid (sol) state at room temperature.

Examples 30 to 46

[0115] An adhesive was obtained in the same manner as in Example 29 except that the type of the modified polyvinyl butyral, the amount of the reactive diluent, and the like were as shown in Table 4. The obtained adhesive was in a liquid (sol) state at room temperature.

(Evaluation)

[0116] The adhesives obtained in the examples and comparative examples were evaluated concerning the adhesiveness to various materials by the above method.

[0117] The results are shown in Tables 3 and 4.

TABLE-US-00003 TABLE 3 Reactive diluent (Modified) polyvinyl acetal (parts by weight) Acetyl Hydroxy Imine (Meth) Degree of group group modification acrylic Epoxy Degree of acetalization content content content reactive reactive polymerization (mol %) (mol %) (mol %) (mol %) diluent diluent Example 11 600 77.5 0.4 20.0 1.7 60 Example 12 600 77.5 0.4 20.0 1.7 100 Example 13 600 77.5 0.4 20.0 1.7 150 Example 14 600 77.5 0.4 20.0 1.7 300 Example 15 600 77.5 0.4 20.0 1.7 900 Example 16 600 77.5 0.4 20.0 1.7 1500 Example 17 600 77.5 0.4 20.0 1.7 2000 Example 18 600 77.5 0.4 20.0 1.7 3000 Example 19 600 77.5 0.4 20.0 1.7 10000 Example 20 600 70.0 0.3 20.9 8.3 60 Example 21 600 70.0 0.3 20.9 8.3 100 Example 22 600 70.0 0.3 20.9 8.3 150 Example 23 600 70.0 0.3 20.9 8.3 300 Example 24 600 70.0 0.3 20.9 8.3 900 Example 25 600 70.0 0.3 20.9 8.3 1500 Example 26 600 70.0 0.3 20.9 8.3 2000 Example 27 600 70.0 0.3 20.9 8.3 3000 Example 28 600 70.0 0.3 20.9 8.3 10000 Polymerization initiator (parts by weight) Perester Imidazole polymerization polymerization Tensile lap-shear strength (MPa) initiator initiator Glass Aluminum SUS PC Acrylic Nylon Example 11 3.0 26.3 4.4 7.8 9.8 8.5 5.4 Example 12 5.0 43.0 38.0 35.4 7.6 8.2 9.1 Example 13 7.5 22.9 22.9 19.8 6.6 7.0 8.7 Example 14 15.0 20.5 20.7 18.2 6.2 6.1 8.0 Example 15 45.0 19.3 19.2 17.1 4.4 5.2 6.4 Example 16 75.0 14.1 15.8 15.2 4.0 3.8 4.1 Example 17 125.0 13.9 15.5 14.9 3.9 3.6 3.8 Example 18 150.0 13.7 15.3 14.1 3.6 3.2 3.0 Example 19 500.0 13.7 15.2 13.3 3.0 2.8 2.6 Example 20 3.0 27.9 6.8 8.5 10.0 8.7 5.8 Example 21 5.0 51.2 45.3 40.3 7.7 8.7 10.2 Example 22 7.5 36.3 32.4 20.2 6.8 7.5 9.2 Example 23 15.0 20.7 21.0 18.5 6.3 6.2 8.1 Example 24 45.0 19.4 19.2 18.0 4.6 6.1 6.8 Example 25 75.0 18.4 19.1 17.7 4.4 6.0 6.5 Example 26 125.0 18.0 18.8 17.4 4.2 5.6 6.1 Example 27 150.0 14.1 15.6 14.8 3.7 3.3 3.4 Example 28 500.0 13.8 15.3 14.2 3.1 3.0 2.9

TABLE-US-00004 TABLE 4 Reactive diluent (Modified) polyvinyl acetal (parts by weight) Acetyl Hydroxy Imine (Meth) Degree of group group modification acrylic Epoxy Degree of acetalization content content content reactive reactive polymerization (mol %) (mol %) (mol %) (mol %) diluent diluent Example 29 600 77.5 0.4 20.0 1.7 60 Example 30 600 77.5 0.4 20.0 1.7 100 Example 31 600 77.5 0.4 20.0 1.7 150 Example 32 600 77.5 0.4 20.0 1.7 300 Example 33 600 77.5 0.4 20.0 1.7 900 Example 34 600 77.5 0.4 20.0 1.7 1500 Example 35 600 77.5 0.4 20.0 1.7 2000 Example 36 600 77.5 0.4 20.0 1.7 3000 Example 37 600 77.5 0.4 20.0 1.7 10000 Example 38 600 70.0 0.3 20.9 8.3 60 Example 39 600 70.0 0.3 20.9 8.3 100 Example 40 600 70.0 0.3 20.9 8.3 150 Example 41 600 70.0 0.3 20.9 8.3 300 Example 42 600 70.0 0.3 20.9 8.3 900 Example 43 600 70.0 0.3 20.9 8.3 1500 Example 44 600 70.0 0.3 20.9 8.3 2000 Example 45 600 70.0 0.3 20.9 8.3 3000 Example 46 600 70.0 0.3 20.9 8.3 10000 Polymerization initiator (parts by weight) Perester Imidazole polymerization polymerization Tensile lap-shear strength (MPa) initiator initiator Glass Aluminum SUS PC Acrylic Nylon Example 29 15 26.0 4.5 7.9 9.8 8.5 5.4 Example 30 25 48.0 33.2 27.2 3.3 3.9 13.2 Example 31 37.5 39.4 24.0 20.8 2.8 3.5 12.9 Example 32 75 33.1 20.2 18.1 2.6 3.3 12.5 Example 33 225 31.1 18.2 17.8 2.4 3.1 12.1 Example 34 375 23.0 15.8 15.2 2.4 3.1 12.0 Example 35 625 13.9 15.5 14.9 2.2 3.0 10.9 Example 36 750 13.8 10.5 12.9 2.1 3.0 10.8 Example 37 2500 13.8 9.4 9.3 2.0 2.9 9.9 Example 38 15 26.1 4.6 8.0 9.8 8.5 5.5 Example 39 25 53.0 35.7 27.3 3.4 4.0 13.3 Example 40 37.5 49.0 30.8 24.5 2.9 3.8 12.8 Example 41 75 40.2 27.8 20.1 2.7 3.5 12.6 Example 42 225 34.5 22.3 19.9 2.6 3.4 12.5 Example 43 375 31.0 22.1 19.9 2.6 3.3 12.5 Example 44 625 30.2 21.5 19.8 2.2 3.3 12.3 Example 45 750 29.8 16.8 19.6 2.2 3.3 12.1 Example 46 2500 14.2 15.9 16.6 2.1 3.1 10.8

[0118] Tables 3 and 4 indicate that even in the case where the amounts of the reactive diluent and polymerization initiator are changed, adhesives within the scope of these examples can exhibit adhesiveness both when the adherends are inorganic material and when the adherend are organic materials. Here, the tables indicate that the adhesiveness tends to decrease as the amounts of the reactive diluent and polymerization initiator are increased. This is presumably because as the amounts of the reactive diluent and polymerization initiator are increased, the amount of the modified polyvinyl acetal having an imine structure is relatively decreased, which in turn results in a decrease in the amount of the constitutional unit having an imine structure.

INDUSTRIAL APPLICABILITY

[0119] The present invention provides an adhesive that has excellent adhesiveness to both organic materials (particularly, polycarbonate, acrylic, and nylon) and inorganic materials, is capable of exhibiting excellent transparency and toughness, and also has excellent handleability.

REFERENCE SIGNS LIST

[0120] 1 Substrate [0121] 2 Support (of the same thickness and material as the substrate) [0122] 3 Bonding portion [0123] 4 Grip