Resin composition for adhesive, adhesive, and adhesion structure

Abstract

The present invention provides a resin composition for an adhesive, being useful as a component of an adhesive having a favorable adhesion property to glass and giving favorable appearance after adhesion. The resin composition for an adhesive contains a polyhydroxyurethane resin. This polyhydroxyurethane resin contains a structural unit formed by polymerizing a compound (A) having at least two five-membered cyclic carbonate structures and a compound (B) having at least two primary amino groups, the polyurethane resin contains a urethane bond, a hydroxy group, and a secondary amino group in the structural unit. Further, this polyhydroxyurethane resin has an amine number of 1 to 50 mgKOH/g and has a hydroxyl number of 10 to 230 mgKOH/g.

Claims

1. A resin composition for an adhesive, comprising a polyhydroxyurethane resin comprising a structural unit formed by polymerizing a compound (A) having at least two five-membered cyclic carbonate structures and a compound (B) having at least two primary amino groups, the polyhydroxyurethane resin comprising a urethane bond, a hydroxy group, and a secondary amino group in the structural unit, wherein the polyhydroxyurethane resin has an amine number of 1 to 50 mgKOH/g, and the polyhydroxyurethane resin has a hydroxyl number of 10 to 230 mgKOH/g.

2. The resin composition for an adhesive according to claim 1, wherein the polyhydroxyurethane resin has a number average molecular weight of 3000 to 100000.

3. The resin composition for an adhesive according to claim 1, wherein the polyhydroxyurethane resin further comprises a structure derived from a polyol having a number average molecular weight of 500 to 3000 in the structural unit.

4. The resin composition for an adhesive according to claim 3, wherein a content proportion of the structure derived from the polyol is 5 to 70% by mass based on the total mass of the polyhydroxyurethane resin.

5. The resin composition for an adhesive according to claim 1, wherein the compound (A) comprises a compound (aII) further having a structure derived from a polyol having a number average molecular weight of 500 to 3000.

6. The resin composition for an adhesive according to claim 1, wherein the compound (B) comprises a compound (b) having a primary amino group at both ends and having at least one secondary amino group in a molecule thereof.

7. The resin composition for an adhesive according to claim 1, wherein the adhesive is an adhesive for glass.

8. An adhesive comprising: the resin composition for an adhesive according to claim 1; and an epoxy-based curing agent having at least two epoxy groups.

9. An adhesion structure comprising: a first base material made of glass; and a second base material adhered to the first glass through the adhesive according to claim 8.

Description

EXAMPLES

(1) Hereinafter, the resin composition for an adhesive of one embodiment of the present invention will more specifically be described giving Examples and Comparative Examples, but is not limited to the following Examples. Note that hereinafter, each of “parts” and “%” is on a mass basis (“parts by mass” and “% by mass” respectively) unless otherwise noted.

Synthesis of Cyclic Carbonate Compound (A)

(2) Synthesis Example 1; Compound (aI-1)

(3) In a reaction container equipped with a stirrer, a thermometer, a gas-introducing tube, and a reflux condenser, 100 parts of bisphenol A diglycidyl ether (trade name “Epotohto YD-128,” manufactured by NIPPON STEEL Chemical & Material CO., LTD.) having an epoxy equivalent of 187 g/eq., 100 parts of N-methyl-2-pyrrolidone (NMP), and 20 parts of sodium iodide (manufactured by FUJIFILM Wako Pure Chemical Corporation) were placed and uniformly dissolved to prepare a solution. The solution was reacted at 100° C. for 10 hours under stirring while a carbonic acid gas was being introduced into the reaction container at a rate of 0.5 L/min. After the completion of the reaction, 2000 parts of isopropyl alcohol was added, and a precipitated white precipitate was separated by filtration and dried with a drier to obtain a white powder.

(4) The obtained powder was analyzed by IR using an infrared spectrophotometer (trade name “FT-720,” manufactured by HORIBA, Ltd.) to find that an absorption peak around 910 cm.sup.−1 attributable to the epoxy group of the raw material had disappeared and an absorption peak around 1800 cm.sup.−1 attributable to a carbonate group (carbonyl group) had newly appeared. Therefore, it was ascertained that the obtained powder is a compound which has a carbonate group having a cyclic structure formed by the reaction between the epoxy group and carbon dioxide, and which is represented by the following chemical formula (aI-1) (hereinafter, referred to as “compound (aI-1)”). Note that IR analysis in the following Synthesis Examples and Production Examples was also performed using the above-described apparatus.

(5) ##STR00011##

(6) Synthesis Example 2; Compound (aI-2)

(7) A white powder was obtained in the same manner as in the reaction procedure and the procedure after the reaction, described in Synthesis Example 1 above, except that bisphenol A diglycidyl ether used in Synthesis Example 1 was changed to resorcinol diglycidyl ether (trade name “DENACOL EX-201,” manufactured by Nagase Chemtex Corporation) having an epoxy equivalent of 117 g/eq. The obtained powder was analyzed by IR in the same manner as in the analysis method described in Synthesis Example 1, and as a result, it was ascertained that the obtained powder is a compound represented by the following chemical formula (aI-2) (hereinafter, referred to as “compound (aI-2)”).

(8) ##STR00012##

(9) Synthesis Example 3; Compound (aI-3)

(10) A reaction was performed in the same manner as in the reaction procedure described in Synthesis Example 1 above, except that bisphenol A diglycidyl ether used in Synthesis Example 1 was changed to neopentyl glycol diglycidyl ether (trade name “DENACOL EX-211,” manufactured by Nagase Chemtex Corporation) having an epoxy equivalent of 138 g/eq. After the completion of the reaction, 400 parts of ethyl acetate and 800 parts of water were added, and a resultant mixture was stirred for 1 hour. Thereafter, the ethyl acetate phase was recovered, and solvent removal was performed with an evaporator to obtain a compound in the form of viscous liquid. The obtained compound was analyzed by IR in the same manner as in the analysis method described in Synthesis Example 1, and as a result, it was ascertained that the obtained compound is a compound represented by the following chemical formula (aI-3) (hereinafter, referred to as “compound (aI-3)”).

(11) ##STR00013##

(12) Synthesis Example 4; Compound (aII-1)

(13) In a reaction container equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts of a polyester polyol (trade name “KURARAY POLYOL P-1010,” manufactured by Kuraray Co., Ltd.) having a number average molecular weight of 1000 and 33.6 parts of hexamethylene diisocyanate (HDI) were placed. Then, N,N-dimethylformamide (DMF) was put therein in such a way that the solid content was 30%, and a resultant mixture was dissolved uniformly and thereafter a resultant solution was reacted at 60° C. for 7 hours. Then, after it was ascertained that the isocyanate content by percentage (NCO %) became 1.6%, 23.6 parts of glycerin carbonate was added, and a resultant mixture was reacted further for 5 hours. The completion of the reaction was ascertained by disappearance of the NCO peak around 2260 cm.sup.−1 by means of IR analysis. In this way, a compound having two five-membered cyclic carbonate structures and having a structure derived from the polyester polyol having a number average molecular weight of 1000 (hereinafter, referred to as “compound (aII-1)”) was obtained.

(14) Synthesis Example 5; Compound (aII-2)

(15) In a reaction container equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts of polyethylene glycol having a number average molecular weight of 1500 and 29.6 parts of isophorone diisocyanate (IPDI) were placed. Then, N,N-dimethylformamide (DMF) was put therein in such a way that the solid content was 30%, and a resultant mixture was dissolved uniformly and thereafter a resultant solution was reacted at 60° C. for 7 hours. Then, after it was ascertained that the isocyanate content by percentage (NCO %) became 1.16%, 15.75 parts of glycerin carbonate was added, and a resultant mixture was reacted further for 5 hours. The completion of the reaction was ascertained by disappearance of the NCO peak around 2260 cm.sup.−1 by means of IR analysis. In this way, a compound having two five-membered cyclic carbonate structures and having a structure derived from a polyether polyol having a number average molecular weight of 1500 (hereinafter, referred to as “compound (aII-2)”) was obtained.

(16) Synthesis Example 6; Compound (aII-3)

(17) In a reaction container equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts of a polycarbonate polyol (trade name “ETERNACOLL UH200,” manufactured by UBE Corporation) having a number average molecular weight of 2000 and 17.42 parts of tolylene diisocyanate (TDI) were placed. Then, N,N-dimethylformamide (DMF) was put therein in such a way that the solid content was 30%, and a resultant mixture was dissolved uniformly and thereafter a resultant solution was reacted at 60° C. for 7 hours. Then, after it was ascertained that the isocyanate content by percentage (NCO %) became 0.98%, 11.81 parts of glycerin carbonate was added, and a resultant mixture was reacted further for 5 hours. The completion of the reaction was ascertained by disappearance of the NCO peak around 2260 cm.sup.−1 by means of IR analysis. In this way, a compound having two five-membered cyclic carbonate structures and having a structure derived from a polycarbonate polyol having a number average molecular weight of 2000 (hereinafter, referred to as “compound (aII-3)”) was obtained.

Production of Polyhydroxyurethane Resin

(18) Production Example 1; HPU 1

(19) A reaction container equipped with a stirrer, a thermometer, and a reflux condenser was prepared, and the inside thereof was replaced with nitrogen, and thereafter 30 parts of the compound (aI-1) obtained in Synthesis Example 1, 70 parts of the compound (aII-1) obtained in Synthesis Example 4, 8.90 parts of hexamethylenediamine (HMD), and 3.39 parts of diethylenetriamine (DETA) were placed therein. Then, N,N-dimethylformamide (DMF) was put therein in such a way that the solid content was 35%, and a resultant mixture was uniformly dissolved, and a resultant solution was reacted at 80° C. for 10 hours under stirring to obtain a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 1”). The obtained resin (HPU 1) was analyzed by IR to find that an absorption peak around 1800 cm.sup.−1 attributable to the carbonate group (carbonyl group) had disappeared and an absorption peak around 1760 cm.sup.−1 attributable to the carbonyl group of a urethane bond had newly appeared. From the above results, it was ascertained that HPU 1 containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A), which includes the compound (aI-1) and the compound (aII-1), and the compound (B), which includes HMD and DETA, was obtained.

(20) Production Example 2; HPU 2

(21) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 5 parts of the compound (aI-3) obtained in Synthesis Example 3, 95 parts of the compound (aII-2) obtained in Synthesis Example 5, 7.02 parts of meta-xylenediamine (MXDA), and 0.84 parts of triethylenetetramine (TETA) were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 2”) was obtained in the same manner as in Production Example 1. HPU 2 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 2 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(22) Production Example 3; HPU 3

(23) A reaction container equipped with a stirrer, a thermometer, and a reflux condenser was prepared, and the inside thereof was replaced with nitrogen, and thereafter 10 parts of bisphenol A glycidyl ether (trade name “Epotohto YD-128,” manufactured by NIPPON STEEL Chemical & Material CO., LTD.; described as “Epoxy compound 1” in Table 2 below) and 45.9 parts of 1,12-diaminododecane (DAD) were placed therein. Then, N,N-dimethylformamide (DMF) was put therein in such a way that the solid content was 35%, and a resultant mixture was uniformly dissolved and thereafter a resultant solution was reacted at 80° C. for 10 hours under stirring. Subsequently, 50 parts of the compound (aI-2) obtained in Synthesis Example 2 and 50 parts of the compound (aII-3) obtained in Synthesis Example 6 were placed therein, and a resultant mixture was reacted at 80° further for 10 hours to obtain a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 3”). HPU 3 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 3 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(24) Production Example 4; HPU 4

(25) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 30 parts of the compound (aI-1) obtained in Synthesis Example 1, 70 parts of the compound (aII-1) obtained in Synthesis Example 4, 3.82 parts of HMD, and 7.90 parts of DETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 4”) was obtained in the same manner as in Production Example 1. HPU 4 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 4 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(26) Production Example 5; HPU 5

(27) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 30 parts of the compound (aI-1) obtained in Synthesis Example 1, 70 parts of the compound (aII-1) obtained in Synthesis Example 4, 11.45 parts of HMD, and 1.13 parts of DETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 5”) was obtained in the same manner as in Production Example 1. HPU 5 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 5 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(28) Production Example 6; HPU 6

(29) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 50 parts of the compound (aI-1) obtained in Synthesis Example 1, 11.32 parts of HMD, and 1.12 parts of DETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 6”) was obtained in the same manner as in Production Example 1. HPU 6 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 6 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(30) Production Example 7; HPU 7

(31) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 50 parts of the compound (aI-3) obtained in Synthesis Example 3, 24.77 parts of DAD, and 2.01 parts of TETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 7”) was obtained in the same manner as in Production Example 1. HPU 7 was analyzed by IR in the same manner as in the analysis method described in Production Example 1, and as a result, it was ascertained that HPU 7 as well as HPU 1, containing a urethane bond, a hydroxy group, and a secondary amino group in a structural unit formed by polymerizing the compound (A) and the compound (B), was obtained.

(32) Production Example 8; HPU 8

(33) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 30 parts of the compound (aI-1) obtained in Synthesis Example 1, 70 parts of the compound (aII-1) obtained in Synthesis Example 4, and 11.29 parts of DETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 8”) was obtained in the same manner as in Production Example 1.

(34) Production Example 9; HPU 9

(35) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 90 parts of the compound (aI-2) obtained in Synthesis Example 2, 10 parts of the compound (aII-1) obtained in Synthesis Example 4, 29.90 parts of HMD, and 2.95 parts of DETA were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 9”) was obtained in the same manner as in Production Example 1.

(36) Production Example 10; HPU 10

(37) In place of the compound (aI-1) and the compound (aII-1), and HMD and DETA, which were used in Production Example 1, 30 parts of the compound (aI-1) obtained in Synthesis Example 1, 70 parts of the compound (aII-1) obtained in Synthesis Example 4, and 12.72 parts of HMD were used. Except for those described above, a solution of a polyhydroxyurethane resin (hereinafter, referred to as “HPU 10”) was obtained in the same manner as in Production Example 1.

(38) Production Example 11; PU 1

(39) A reaction container equipped with a stirrer, a thermometer, and a reflux condenser was prepared, and the inside thereof was replaced with nitrogen, and thereafter 50 parts of a polyester polyol (trade name “KURARAY POLYOL P-1010,” manufactured by Kuraray Co., Ltd.; described as “Polyol compound 1” in Table 2 below) having a number average molecular weight of 1000, 50 parts of 2,2′-[isopropylidenebis[(p-phenylene)(oxy)]] diethanol (manufactured by FUJIFILM Wako Chemical Corporation; described as “Diol compound 1” in Table 2 below), and 29.20 parts of hexamethylene diisocyanate (HDI) were placed therein. Then, DMF was put therein in such a way that the solid content was 35%, and a resultant mixture was uniformly dissolved and thereafter a resultant solution was reacted at 80° C. for 10 hours under stirring. The completion of the reaction was ascertained by the disappearance of the NCO peak around 2260 cm.sup.−1 by means of IR analysis, and thus a solution of a polyurethane prepolymer (hereinafter, referred to as “PU 1”) was obtained.

(40) The amine numbers, hydroxyl numbers, and number average molecular weights of the resins (HPU 1 to 10, and PU 1) obtained in the respective Production Examples described above were measured by the methods described below.

(41) (Amine Number)

(42) The amine numbers of the resins (HPU 1 to 10, and PU 1) obtained in the respective Production Examples described above were measured as follows. Each resin solution was weighed in an amount of 1 g in terms of solid content (resin) and dissolved in N,N-dimethylformamide (DMF). The dissolved resin solution was titrated by potentiometric titration with 0.05 mol/L of hydrochloric acid, and the amine number (mgKOH/g) was calculated according to the following formula (1).

(43) $\begin{array}{cc}\mathrm{Amine}\mathrm{number}\left(\frac{\mathrm{mgKOH}}{g}\right)=\frac{\mathrm{titer}\left(\mathrm{mL}\right)\times 0.05\times 56.1}{\mathrm{mass}\mathrm{of}\mathrm{solid}\mathrm{content}\mathrm{of}\mathrm{resin}\left(g\right)}& \left(1\right)\end{array}$

(44) (Hydroxyl Number)

(45) The hydroxyl numbers (mgKOH/g) of the resins (HPU 1 to 10, and PU 1) obtained in the respective Production Examples described above were measured as follows in accordance with the neutralization titration method specified in JIS K 1557-1. A sample was weighed according to Table 1 below, and 5 mL of an acetylation reagent (obtained by adding pyridine to 25 g of acetic anhydride in such a way that the total volume was 100 mL) was added thereto, and a resultant mixture was reacted at 95 to 100° C. for 1 hour. After the reaction followed by radiational cooling, 1 mL of water was added to the reaction solution, and the reaction solution was shaken and heated again at 95 to 100° C. for 10 minutes, and thus acetic anhydride was decomposed. After radiation cooling, a few drops of phenolphthalein was added as an indicator to perform titration with 0.5 mol/L of an ethanol solution of potassium hydroxide, and the end point was defined as the point in time when pale red color was retained for about 30 seconds. The same operation was performed without using the sample as a blank test. Then, the hydroxyl number was calculated according to the following formula (2).

(46) TABLE-US-00001 TABLE 1 Total value of hydroxyl number and Mass of amine value (mgKOH/g) sample (g)  10 or more and less than 100 2.00 100 or more and less than 150 1.50 150 or more and less than 200 1.00 200 or more and less than 250 0.75 250 or more and less than 300 0.70

(47) $\begin{array}{cc}\mathrm{Hydroxyl}\mathrm{number}\left(\frac{\mathrm{mgKOH}}{g}\right)=\frac{\left(A-B\right)\times 0.5\times 56.1}{\mathrm{mass}\mathrm{of}\mathrm{solid}\mathrm{content}\mathrm{of}\mathrm{resin}\left(g\right)}-\mathrm{amine}\mathrm{number}& \left(2\right)\end{array}$

(48) wherein

(49) A: amount (mL) of 0.5 mol/L ethanol solution of potassium hydroxide used for blank test

(50) B: amount (mL) of 0.5 mol/L ethanol solution of potassium hydroxide used for titration

(51) (Number Average Molecular Weight)

(52) The number average molecular weights of the resins (HPU 1 to 10, and PU 1) obtained in the respective Production Examples described above were measured by GPC under the following conditions.

(53) Apparatus: GPC apparatus (trade name “GPC-8820,” manufactured by Tosoh Corporation)

(54) Columns: 4 columns (trade name “Super AW2500, AW3000, AW4000, and AW5000,” manufactured by Tosoh Corporation)

(55) Eluent: N,N-dimethylformamide (DMF)

(56) Injection volume: 50 μL

(57) Flow rate: 0.5 mL/min

(58) Measurement temperature: 40° C.

(59) Detector: RI detector bult in GPC-8820

(60) Standard substance: standard polystyrene

(61) Results of the measurement of the amine numbers, hydroxyl numbers, and number average molecular weights of the resins obtained in the respective Production Examples described above are shown together with the materials used for production of the respective resins and the amounts (units: parts) of thereof in Table 2 (Table 2-1 and Table 2-2). In Table 2, the content proportion (%) of the structure derived from a polyol, based on the total mass of the resin (solid content), is also shown as “Polyol content ratio (%).” This polyol content ratio was calculated from the use amount of the monomer raw materials for forming the resin.

(62) TABLE-US-00002 TABLE 2-1 Materials used for production of resins and amounts thereof (units: parts by mass), and characteristics of obtained resins Production Example No. (Resin No.) 1 2 3 4 5 6 7 (HPU 1) (HPU 2) (HPU 3) (HPU 4) (HPU 5) (HPU 6) (HPU 7) Compound (aI-1) 30 30 30 50 Compound (aI-2) 50 Compound (aI-3) 5 50 Compound (aII-1) 70 70 70 Compound (aII-2) 95 Compound (aII-3) 50 Epoxy compound 1 10 HMD 8.90 3.82 11.45 11.32 DAD 45.9 24.77 MXDA 7.02 DETA 3.39 7.90 1.13 1.12 TETA 0.84 2.01 Polyol compound 1 Diol compound 1 HDI Polyol content ratio (%) 39.6 60.6 24.8 39.8 39.54 0 0 Hydroxyl number (mgKOH/g) 109.40 59.62 165.00 109.94 109.10 194.52 200.77 Amine number (mgKOH/g) 16.40 5.96 38.48 38.48 5.46 9.73 20.08 Number average molecular weight 10000 6000 50000 12000 12000 11000 15000

(63) TABLE-US-00003 TABLE 2-2 Materials used for production of resins and amounts thereof (units: parts by mass), and characteristics of obtained resins Production Example No. (Resin No.) 8 9 10 11 (HPU 8) (HPU 9) (HPU 10) (PU 1) Compound (aI-1) 30 30 Compound (aI-2) 90 Compound (aI-3) Compound (aII-1) 70 10 70 Compound (aII-2) Compound (aII-3) Epoxy compound 1 HMD 29.90 12.72 DAD MXDA DETA 11.29 2.95 TETA Polyol compound 1 50 Diol compound 1 50 HDI 29.20 Polyol content 40.0 4.78 39.5 38.1 ratio (%) Hydroxyl number 110.36 241.48 108.96 30.1 (mgKOH/g) Amine number 55.18 12.07 0.00 — (mgKOH/g) Number average 10000 10000 10000 10000 molecular weight

Preparation of Adhesive Composition

(64) Adhesive compositions of Examples 1 to 7 and Comparative Examples 1 to 5 were prepared using the solutions of the resins (HPU 1 to 10, and PU 1) obtained in the respective Production Examples described above, and epoxy-based curing agents (EP 1, EP 2, and EP 3) and an isocyanate-based curing agent (NCO 1), which are described below. The types and blending amounts of the resins and curing agents, which were used, are as shown in upper rows (units: parts in terms of solid content) in Table 3 (Table 3-1 and Table 3-2). Note that the blending amount of the epoxy-based curing agent in Examples and Comparative Examples 1 and 2 was determined in such a way that the equivalent ratio of the epoxy group of the epoxy-based curing agent to the secondary amino group of the polyhydroxyurethane resin (HPU) gave the value shown in “Equivalent ratio (E/A)” column in Table 3.

(65) EP 1: polyglycerol polyglycidyl ether (having an epoxy equivalent of 168 g/eq., trade name “DENACOL EX-512,” manufactured by Nagase Chemtex Corporation)

(66) EP 2: epoxidized polybutadiene (having an epoxy equivalent of 200 g/eq., trade name “NISO-PB JP-100,” manufactured by Nippon Soda Co., Ltd.)

(67) EP 3: glycerol polyglycidyl ether (having an epoxy equivalent of 144 g/eq., trade name “DENACOL EX-314,” manufactured by Nagase Chemtex Corporation)

(68) NCO 1: HDI biuret (NCO % =23.5%, trade name “Duranate 24A-100,” manufactured by Asahi Kasei Corp.)

Evaluation Method

(69) (Tensile Lap-Shear Strength)

(70) A test specimen was prepared for each of Examples and Comparative Examples in the manner as described below using the prepared adhesive compositions. As adherends, two glass plates each having a width of 25 mm, a length of 150 mm, and a thickness of 3 mm were prepared, and the surfaces of the glass plates were washed with ethanol. Each of the adhesive compositions was applied on a region of a length of 10 mm from the one end (width of 25 mm) of one of the glass plates (one end side region of 25 mm×10 mm) with a bar coater in such a way that the thickness after drying was 0.2 mm. Subsequently, another glass plate was overlapped and pasted with the applied surface in the region of a length of 10 mm from the one end (width of 25 mm) thereof in such a way that the overlapped region of the two glass plates coincides with the region of the applied surface, and then the glass plates were temporarily fixed with a crip. A curing reaction was performed under a condition of 60° C. for 24 hours with the state retained as it was, and thus a test specimen for a tensile lap-shear strength test was prepared (see, the test piece described in JIS K6850 “Determination of tensile lap-shear strength of rigid-to-rigid bonded assemblies”).

(71) The tensile lap-shear strength (MPa) of each of the prepared test specimens was measured using a tensile tester (trade name “AGS-X 10kN,” manufactured by Shimadzu Corporation) under a condition of a tensile speed of 50 mm/min in an environment of 20° C. and 60% RH. The measured value of the tensile lap-shear strength was recorded, and the adhesion property to glass was evaluated based on the measured value according to the following evaluation criteria.

(72) A: the tensile lap-shear strength is 5 MPa or more.

(73) B: the tensile lap-shear strength is 3 MPa or more and less than 5 MPa.

(74) C: the tensile lap-shear strength is less than 3 MPa.

(75) (Appearance after Adhesion)

(76) The appearance of the test specimen for each of the prepared test specimens was visually checked to evaluate the appearance after adhesion according to the following evaluation criteria.

(77) Excellent: a bubble is not ascertained at all in the test specimen.

(78) Poor: a bubble is ascertained in the test specimen.

(79) Results of the above-described evaluation are shown in Table 3 (Table 3-1 and Table 3-2).

(80) TABLE-US-00004 TABLE 3-1 Combinations of adhesive compositions (units: parts by mass) and evaluation results Example Example Example Example Example Example Example 1 2 3 4 5 6 7 HPU 1 100 HPU 2 100 HPU 3 100 HPU 4 100 HPU 5 100 HPU 6 100 HPU 7 100 HPU 8 HPU 9 HPU 10 PU 1 EP 1 4.91 11.52 1.63 2.91 6.01 EP 2 1.59 EP 3 14.80 NCO 1 Equivalent 1.0 0.75 1.5 1.0 1.0 1.0 1.0 ratio (E/A) Tensile lap-shear 4.5 6.2 4.0 4.3 5.5 3.1 3.5 strength (Mpa) Adhesion property B A B B A B B Appearance Excellent Excellent Excellent Excellent Excellent Excellent Excellent

(81) TABLE-US-00005 TABLE 3-2 Combinations of adhesive compositions (units: parts by mass) and evaluation results Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 HPU 1  HPU 2  HPU 3  HPU 4  HPU 5  HPU 6  HPU 7  HPU 8  100 HPU 9  100 HPU 10 100 100 PU 1 100 EP 1 EP 2 4.30 EP 3 14 .20 NCO 1 17.30 9.60 Equivalent ratio (E/A) 1.0 1.0 — — — Tensile lap-shear 2.3 1.7 1.2 2.0 2.1 strength (MPa) Adhesion property C C C C C Appearance Excellent Excellent Excellent Poor Poor

(82) As shown in Table 3, it was ascertained that the adhesive compositions of Examples 1 to 7 exhibit favorable adhesion force to glass. In contrast, sufficient adhesive force was not obtained from any of the adhesive compositions of Comparative Examples 1 to 5. With regard to the adhesive composition of Comparative Example 1, it is considered that this is because the amine number of HPU 8 used as a component of the adhesive composition was too high and therefore the crosslink density was too high after adhesion (after curing). With regard to the adhesive composition of Comparative Example 2, it is considered that the hydroxyl number of HPU 9 used as a component of the adhesive composition was too high, therefore the resin after adhesin (after curing) had poor flexibility and a hard-and-brittle characteristic, and therefore the adhesive composition did not exhibit adhesion force. In the adhesive composition of Comparative Example 3, a curing agent was not used for HPU 10 not having a secondary amino group, and in the adhesive composition of Comparative Example 4, the isocyanate-based curing agent was used for HPU 10 not having a secondary amino group. From the results of Comparative Examples 3 and 4 and the results of Examples, it was inferred that the curing reaction between the secondary amino group in the particular polyurethane resin and the epoxy group in the epoxy-based curing agent contributes to the adhesion property.

(83) With regard to the appearance after adhesion, the results were favorable in Examples 1 to 7 and Comparative Examples 1 to 3, and therefore it was found that by using the epoxy-based curing agents for the polyhydroxyurethane resins without using the isocyanate-based curing agent, the appearance after adhesion can be made favorable.