NOVEL INCLUSION COMPOUND

Abstract

A method includes mixing a clathrate compound with an epoxy resin to form a curable epoxy resin composition, and may further include heating the curable epoxy resin composition to cure the curable epoxy resin composition. The clathrate compound includes (a1) a carboxylic acid compound represented by the formula A(COOH).sub.k; and (a2) a xylylene diamine compound. In the formula A(COOH).sub.k, A represents a C1-C6 linear hydrocarbon group optionally having a substituent, a C3-C10 monocyclic hydrocarbon group optionally having a substituent, or a C6-C10 bicyclic hydrocarbon group optionally having a substituent; and k represents 2 or 3.

Claims

1. A method comprising: mixing a clathrate compound with an epoxy resin to form a curable epoxy resin composition, wherein the clathrate compound comprises the following (a1) and (a2): (a1) a carboxylic acid compound represented by formula (II):
A(COOH).sub.k(II) wherein A represents a C1-C6 linear hydrocarbon group optionally having a substituent, a C3-C10 monocyclic hydrocarbon group optionally having a substituent, or a C6-C10 bicyclic hydrocarbon group optionally having a substituent, and k represents 2 or 3; and (a2) a xylylene diamine compound represented by formula (III): ##STR00017##

2. The method according to claim 1, wherein the compound represented by formula (II) of (a1) is a compound represented by formula (IV): ##STR00018## wherein R.sub.1 represents a C1-C6 alkyl group, a C1-C6 alkoxy group, a nitro group, or a hydroxy group.

3. The method according to claim 1, wherein the compound represented by formula (III) of (a2) is a compound represented by formula (V): ##STR00019##

4. The method according to claim 1, further comprising: heating the curable epoxy resin composition to cure the curable epoxy resin composition.

5. The method according to claim 4, wherein the compound represented by formula (II) of (a1) is a compound represented by formula (IV): ##STR00020## wherein R.sub.1 represents a C1-C6 alkyl group, a C1-C6 alkoxy group, a nitro group, or a hydroxy group.

6. The method according to claim 4, wherein the compound represented by formula (III) of (a2) is a compound represented by formula (V): ##STR00021##

Description

EXAMPLES

[0075] While Examples will be shown hereinbelow, the present invention is not bound by these examples in any way.

[0076] The clathrate compound can be also referred to as a catalyst or a curing catalyst hereinbelow.

[0077] Case of a clathrate compound of a xylylene diamine compound and a TEP compound

[0078] (Host Molecule)

[0079] TEP: 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane

[0080] (Guest Molecule)

[0081] MXDA: m-xylylene diamine

[0082] 2E4MZ: 2-ethyl-4-methyl imidazole

[0083] 2P4MHZ: 2-phenyl-4-methyl-5-hydroxymethyl imidazole

[0084] Also, the notation of the clathrate compound is shown in the order from the host compound to the guest compound, and the clathrate ratio (molar ratio) between the host compound and the guest compound is shown in the subsequent parentheses. For example, TEP-MXDA (1/1) means a clathrate compound in which the host compound is TEP and the guest compound is MXDA, and the clathrate ratio is 1/1.

[Example 1] TEP-MXDA (1/2)

[0085] To 7.97 g of TEP, 50 mL of ethyl acetate was added, and the resulting mixture was stirred. A solution of 5.45 g of MXDA diluted with 10 mL of ethyl acetate was added dropwise thereto, and after the addition, the resulting mixture was heated to reflux for three hours. After cooling, filtration and vacuum drying were carried out to thereby yield a clathrate compound, TEP-MXDA (1/2). Yield: 13.13 g. The clathrate compound obtained was subjected to .sup.1H-NMR, TG-DTA, and XRD to confirm clathrate. Additionally, the decomposition point was 178-183 C.

[0086] (Curing Start Temperature of Liquid Curable Epoxy Resin)

[0087] [Measurement Example 1]

[0088] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.2 g of MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 1.

[0089] [Measurement Example 2]

[0090] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.49 g of TEP-MXDA (1/2) (Example 1) was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 1.

[0091] [Measurement Example 3]

[0092] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.56 g of TEP-2E4MZ (1/2) was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 1.

[0093] [Measurement Example 4]

[0094] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.41 g of TEP-2P4MHZ (1/2) was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 1.

TABLE-US-00001 TABLE 1 Curing start temperature Curing start Compound temperature Measurement example 1 MXDA 76 C. Measurement example 2 TEP-MXDA (1/2) 102 C. Measurement example 3 TEP-2E4MZ (1/2) 137 C. Measurement example 4 TEP-2P4MHZ (1/2) 158 C.

[0095] (Storage Stability of Liquid Curable Epoxy Resin)

[0096] [Measurement Example 5]

[0097] To 10 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.4 g of MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was stored at 30 C. and visually observed. Measurement was ended when the composition solidified, and the storage stability was evaluated. The result is shown in Table 2.

[0098] [Measurement Example 6]

[0099] To 10 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.99 g of TEP-MXDA (1/2) was mixed to thereby yield a curable epoxy resin composition. The composition was stored at 30 C. and visually observed. Measurement was ended when the composition solidified, and the storage stability was evaluated. The result is shown in Table 2.

TABLE-US-00002 TABLE 2 Storage stability Example Compound Storage stability Measurement example 5 MXDA Solidifies in two days Measurement example 6 TEP-MXDA (1/2) Solidifies in 10 days

[0100] In comparison of Measurement Example 1 with Measurement Example 2, the composition in which only the guest compound was used as the curing agent can be cured at a lower temperature. However, in comparison of Measurement Example 5 with Measurement Example 6, the epoxy resin composition in which only the guest compound was used as the curing agent started curing reaction at 30 C. and solidified in two days, causing an industrial problem. If the temperature rises at a rate of 10 C./minute, the curing reaction starts at 76 C. Indeed, the curing reaction occurs even at 30 C., and thus, the guest compound, when used as the curing agent, has to be used immediately after mixed with the epoxy resin. However, the clathrate compound of the present invention has sufficient time until it solidifies, causing no industrial problem.

[0101] Alternatively, in comparison with the known clathrate compounds (Measurement Example 3 and Measurement Example 4), it was found that the epoxy resin composition in which the clathrate compound of the present invention (Measurement Example 2) was used as the curing agent had a lower curing start temperature, despite of use of the same TEP as the host compound. Use of the clathrate compound of the present invention as the curing agent enables the epoxy resin to cure at a lower temperature to thereby minimize thermal damage on the epoxy resin. This makes the compound suitable for use for thermally-susceptible epoxy resin. Also, a low heat-resistant material can be used as an adherend for epoxy resin.

[0102] Case of a clathrate compound of a xylylene diamine compound and a carboxylic acid compound

[0103] (Host Molecule)

[0104] NIPA: 5-nitroisophthalic acid

[0105] HIPA: 5-hydroxyisophthalic acid

[0106] (Guest Molecule)

[0107] MXDA: m-xylylene diamine

[0108] Also, the notation of the clathrate compound is shown in the order from the host compound to the guest compound, and the clathrate ratio (molar ratio) between the host compound and the guest compound is shown in the subsequent parentheses. For example, HIPA-MXDA (1/1) means a clathrate compound in which the host compound is HIPA and the guest compound is MXDA, and the clathrate ratio is 1/1.

Example 2

[0109] (HIPA-MXDA)

[0110] To 7.29 g of HIPA, 40 mL of methanol was added, and the resulting mixture was stirred for dissolution. A solution of 5.45 g of MXDA diluted with 10 mL of methanol was added dropwise thereto, and the resulting mixture was heated to reflux, on completion of the dropwise addition, for three hours. After cooling, filtration and vacuum drying were carried out to thereby yield a clathrate compound, HIPA-MXDA (1/1). The clathrate compound obtained was subjected to .sup.1H-NMR, TG-DTA, and XRD to confirm clathrate. Decomposition point: 235-240 C.

Example 3

[0111] (NIPA-MXDA)

[0112] To 8.45 g of NIPA, 40 mL of ethyl acetate was added, and the resulting mixture was stirred for dissolution. A solution of 5.45 g of MXDA diluted with 10 mL of ethyl acetate was added dropwise thereto, and the resulting mixture was heated to reflux, on completion of the dropwise addition, for three hours. After cooling, filtration and vacuum drying were carried out to thereby yield a clathrate compound, NIPA-MXDA (1/1). The clathrate compound obtained was subjected to .sup.1H-NMR, TG-DTA, and XRD to confirm clathration. Decomposition point: 265-270 C.

[0113] (Curing Start Temperature of Liquid Curable Epoxy Resin)

[0114] [Measurement Example 7]

[0115] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.2 g of MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 3.

[0116] [Measurement Example 8]

[0117] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.47 g of HIPA-MXDA (Example 1) was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 3.

[0118] [Measurement Example 9]

[0119] To 5 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.51 g of NIPA-MXDA (Example 2) was mixed to thereby yield a curable epoxy resin composition. The composition was measured by DSC (manufactured by TA instruments, model Q2000) for the curing start temperature of the epoxy resin (extrapolated peak start temperature). The result is shown in Table 3.

TABLE-US-00003 TABLE 3 Curing start temperature Curing start Compound temperature Measurement example 7 MXDA 76 C. Measurement example 8 HIPA-MXDA (1/1) 196 C. Measurement example 9 NIPA-MXDA (1/1) 189 C.

[0120] In comparison with the guest compound which is not included (Measurement Example 7), the epoxy resin compositions in which the clathrate compound of the present invention (Measurement Example s 8 and 9) is used have a higher curing start temperature. This has revealed that the epoxy resin compositions in which the clathrate compound of the present invention is used have improved heat resistance.

[0121] (Storage Stability of Liquid Curable Epoxy Resin)

[0122] [Measurement Example 10]

[0123] To 10 g of an epoxy resin EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.4 g of MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was stored at 30 C. and visually observed. Measurement was ended when the composition solidified, and the storage stability was evaluated. The result is shown in Table 4.

[0124] [Measurement Example 11]

[0125] To 10 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 0.93 g of HIPA-MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was stored at 30 C. and visually observed. Measurement was ended when the composition solidified, and the storage stability was evaluated. The result is shown in Table 4.

[0126] [Measurement Example 12]

[0127] To 10 g of an epoxy resin, EPOTOHTO YD-128 (R: manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., epoxy equivalent 184-194 g/eq), 1.02 g of NIPA-MXDA was mixed to thereby yield a curable epoxy resin composition. The composition was stored at 30 C. and visually observed. Measurement was ended when the composition solidified, and the storage stability was evaluated. The result is shown in Table 4.

TABLE-US-00004 TABLE 4 Storage stability Compound Storage stability Measurement example 10 MXDA Solidifies in two days Measurement example 11 HIPA-MXDA (1/1) Not solidifies in 100 days Measurement example 12 NIPA-MXDA (1/1) Not solidifies in 100 days

[0128] In comparison with MXDA which is not included, it has been revealed that the epoxy resin composition in which the clathrate MXDA is used has significantly improved storage stability.

INDUSTRIAL APPLICABILITY

[0129] The novel clathrate compound of the present invention can be used as a curing agent, a curing accelerator, and the like for epoxy resin.