JPS6055071B2 - Imidazolyl succinic acid compound and epoxy resin curing method using the compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel imidazolyl succinic acid compounds, and further relates to an epoxy resin curing method using each compound.

The novel imidazolyl succinic acid compound of the present invention has the structural formula [wherein R2 is a residue selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an undecyl group, a heptadecyl group, and a phenyl group, and R4 is a Represents a hydrogen atom or a methyl group.

].

The novel compound of the present invention is represented by the following structural formula 1
It can be synthesized by reacting unsubstituted imidazole with maleic acid.

When 1 mol of imidazole unsubstituted at the 1-position and 1 mol or more of maleic acid are heated in the absence of a solvent or in an appropriate solvent for an appropriate period of time, the desired product is produced.

After the reaction is completed, the contents are purified according to a conventional method.

The above-mentioned reaction proceeds satisfactorily even in the absence of a solvent, but in large-scale reactions, it becomes difficult to remove the reaction heat, so the reaction should be carried out in an appropriate solvent to remove the reaction heat, and the reaction heat should be removed rapidly. It is desirable to carry out the reaction while adding maleic acid little by little to the reaction system in order to suppress the occurrence of oxidation. The solvent used is one that is inert to the source system and the product system, typical examples of which are water, methanol, ether, dimethylformamide, and the like.

The reaction temperature should normally be 7QC or higher, but in order to shorten the reaction time, it is preferably 100'C or higher, particularly around 130C.

The reaction is complete within a few hours.

Of course, the desired product can also be obtained by using 1 mol or less of maleic acid per 1 mol of imidazole in this reaction, and after the reaction is completed, unreacted imidazole in the reaction mixture is extracted and removed with a suitable solvent.

Next, the properties of the imidazolyl succinic acid compound constituting the present invention will be shown.

imidazolyl-succinic acid ,Structural formula: acidic colorless crystals Melting point: 〉200℃ Easily soluble in acetic acid.

Soluble in water. Insoluble in alcohol and acetone. TLC(
Silica, EtOH, 12 color development): R, O. OO~ 0.
07ν? rl:3,140,2,820,2,730,
1,960, 1,710, 1,570 (first absorption), 1
,385,1.350,1,320,1,260,1,
175,960,940,900,845,750,7
10NMR (D2O): δ8.85,s,1H (proton at 2nd position); 7.58,s,1H (proton at 4th or 5th position); 7.50,S,1H (proton at 4th or 5th position)
5.40, dd, 1H (-N-CH-CO
O): 3.32, m, Mass: m/El84 (M,
116(HOOC-CH-CH-COOH), 68(
(imidazole) 2-methylimidazolyl-succinic acid Structural formula: Acidic colorless crystal Melting point: >200°C Soluble in water.

Insoluble in alcohol and acetone. TLC (Silica, Et
OH, l2 color development): R, O. OO~ 0.05ν? I
:3430,3145,2680,1370,1610
, 1520, 1400, 1250 (first absorption), 118
0,900,795,740NMR(CF3COOH)
:δ7.53,S,1H (4 or 5 position proton)
;7.41,S,1H (4 or 5 position proton): 5
．． 75, dd, 3H (methyl group) Mass: m/El9
8 (M, 153 (M+-COOH) 108 (15
3-COOH), 81 (108-CHCH2-),
54(81-CH-N=)2-ethylimidazolyl-succinic acid Structural formula: Acidic colorless crystals Melting point: 2000C Soluble in water.

Poorly soluble in methanol. Insoluble in acetone and alcohol. T
LC (silica, EtOH, 12 color development): R, O. OO~
0.05ν? T1: 3250, 3140, 3100
, 2990, 1710, 1625 (first absorption), 160
0,1520,1400,1335,1255,118
5,794,775,736NMR (CD3OD): δ
7.67,d,1H (4 or 5 position proton); 7
．． 47,d,1H (4 or 5 position proton); 5.6
5, dd, 1H (=N--CH--COO); 3.30
, m92H (MiC-CH2COO); 3.14q, Ma
ss:m/E2l2(M+), 167(M+-COOH
), 121 (167-COOH-H), 95 (12
1-CH-CH), 81 (95-N), 54, 45, 4
1,262-undecylimidazolyl-succinic acid Structural formula: Acidic colorless crystals.

Melting point: 210-217C Soluble in methanol.

Insoluble in water, ethanol, and acetone. TLC (Silica, E
tOH, l2 color development): R, O. OO~ 0.10ν: 3240, 3140, 2925, 2850, 1720
,1670,1600,1520,1460,1430
, 1400, 1330, 1265 (first absorption), 117
5,1110,970,950,915,880,78
5,750NMR (CF3COOH): δ7.52,S
, 1H (4 or 5 position proton); 7.42, S,
1H (4 or 5 position proton); 5.78, dd,
1H (=N.-CH----COO); 3.61,
m. 2H (long chain α-position methylene); 1.90, m, 2H
(Long chain β-position methylene); 1.31, m, 161] (Long chain polyethylene); 0.88, m, 3H (Long chain terminal methyl) Mass: m/E338 (M+), 293 (M
+-COOH), 212(293-COOH-CH
CH2), 207(221-N), 193(207-CH-H)2-heptadecyl imidazolyl-succinic acid Structural formula: Acidic colorless crystals.

Melting point: 190-197C Easily soluble in acetic acid.

Soluble in EtOH. Slightly soluble in water and methanol. TLC (silica, EtOH, 12 color development): RfO. OO~ 0.0
5ν? 1:3230,3130,2920,2850,
1720, 1660, NMRl595, l5l5, l4
25, l4OO, l33O, l26O (first absorption), 1
170,1108 (KCH D2O): δ7.16,S
, 1H (4 or 5 position proton); 6.98, s, 1H (
4 or 5 proton); 4.99, m, 4H (-CH2
COO and long chain α-position methylene); 1.68, m, 2H
(Long chain β-position methylene); 1.26, m, 28H (long chain polyethylene); 0.86, m, 3H (long chain terminal methyl) Mass: m/E422 (M, 332 (M+-
COOH- COOH), 305 (332-CHCH
2-), 277(305-diCH-NH-)4-methylimidazolyl-succinic acid Structural formula: Acidic colorless crystals.

Melting point: 〉200℃ Soluble in water.

Insoluble in alcohol and acetone. TLC (Silica, Et
OH, l2 color development): R, O. OO~ 0.04:315
5,3000,1700,1620,1530,z14
20, 1370, 1300, 1240 (first absorption),
1140,940,885850,775,750,7
15NMR (CF3COOD): δ8.74, S, 1H
(2nd proton); 7.30,S,1H (4 or 5
position proton);5.72,t,2H(=C-CH2
COO); 2.44, S, 3H (methyl at 4 or 5 position) M
ass: m/El98 (M+), 153 (M+-COO
H) Ko 108 (153-COOH), 81 (108
-2CH-CH2-), 54 (81-2CH-N=
) 2-Ethyl-4-methylimidazolyl-succinic acid Structural formula: Acidic colorless crystals.

Melting point: 2300C Soluble in water and acetic acid.

Insoluble in alcohol and acetone. TLC (Silica, Et
OH, l2 color development): RfO. OO~ 0.07ν? 1:
3460, 3370, 3110, 2800, 1890,
1685, (first absorption), 1500, 1370, 126
5, (2nd absorption), 1220, 1197, 117
0,965,950,890,805,770,690
,665NMR (CD3OD): δ7.36,S,1H
(4 or 5 position proton); 5.56, dd, 3H
(4th-position methyl); 1.40, t, Mass: m/E226 (M, 181 (M+-COO
H), 136 (181-COOH), 109 (13
6-CH- CH2-), 95 (109-N-),
68,54,45(COOH), 392-undecyl-4-methylimidazolyl succinic acid Structural formula: Acidic colorless crystals.

Melting point: 187-189C Soluble in methanol.

Insoluble in water, ethanol and acetone. TLC (Silica,
EtOH, 12 color development): RfO. OO~ 0.10ν Note 1: 3430, 2920, 2860, 1975, 171
5,1590 (first absorption), 1510,1470,
1420, 1375, 1340, 1315, 1235,
1180,975,950,880,775NMR(C
F3COOD): δ7.12, S, 1H (4 or 5
position proton); 5.72-5.56, dd, 2H (=C
-CH2-COO-); 3.14, t, 2H (long chain α
methylene at position); 2.36, S, 3H (proton at 4 or 5 position); 1.84, m, 2H (methylene at β position of long chain); 1
．． 32, m, 16H (long chain polymethylene); 0.88
, m, 3H (terminal methyl of long chain) Mass: m/E35
2(M,307(M+-COOH),2-phenyl-4-methylimidazolyl succinic acid Structural formula: Acidic colorless crystals.

Melting point: 201~2℃ Soluble in water.

Insoluble in methanol, ethanol and acetone. TLC(
Silica, EtOH, 12 color development): RfO. OO~ 0
．． 07ν presentation I: 3480, 2965, 1725, 164
0,1480,1410,1180,860,710N
MR (CF3COOD): δ 7.67, m, 5H (phenyl); 7.28, s, 1H (4 or 5 position peptidyl)
5.70, dd, 2H (=C-CH2CO
O-): 2.50, S, 3H (methyl at 4 or 5 position) Ma
ss: m/E274 (M, 229 (M+-COOH)
10A'Orin-RCv)H) Next, an epoxy resin curing method using the various imidazolyl-succinic acids described above as a curing agent and curing accelerator will be described.

The term epoxy resin used herein is an abbreviation for an epoxy compound having an average of more than one epoxy group in its molecule.

If the system consisting of epoxy resin and hardener (or hardener and accelerator) has good shelf life and storage stability, the system is called a one-component epoxy resin formulation or a one-component epoxy resin formulation. , included in the system. Generally, the curing agent used is called a latent curing agent, and the curing accelerator is also called a latent accelerator. The succinic acid can be used as a latent curing agent and a latent accelerator. The one-component epoxy resin formulation obtained by the method of the present invention exhibits little increase in system viscosity, which causes a decrease in workability, during long-term storage at room temperature, and is resistant to phase separation (system stability). Also, during curing, it cures quickly and efficiently by heating, giving a cured product with excellent harmonious properties such as electrical insulation, mechanical strength, and chemical resistance7.

The obtained cured product is useful for sealing and insulating coating of various semiconductor parts such as diodes and transistors, and electronic parts such as ceramic capacitors and resistors.

Representative imidazolyl-succinic acid compounds suitable for the practice of the present invention include 2-ethylimidazolyl-succinic acid, 2-ethylimidazolyl-succinic acid,
These include undecylimidazolyl-succinic acid, and they may be used alone or in combination.

The succinic acid is a curing accelerator for the following various curing agent components, or
It is also useful as a co-curing agent.

Namely, aliphatic polyamines, aromatic polyamines, amine salts, quaternary ammonium salts, dicyandia Oamide, urea,
Melamine, polycarboxylic acid, polycarboxylic acid anhydride, polyhydric phenols, condensates of phenols and formaldehyde, polycarboxylic acid hydrazide, etc.

The blending ratio of each type of succinic acid used as a curing agent in the method of the present invention is 0.5 to 30 phr (parts by weight per 10 parts of epoxy resin), and other curing agent accelerators or When used as a co-curing agent, the appropriate blending ratio is 0.01 to 30 phr, preferably 0.05 to 10 phr.

The polyepoxy compound in the present invention contains on average more than one epoxy group per molecule, and this group may be located at the terminal position of the molecule, may be H2-shi-\o/, or may be located in the middle of the molecular formula. -0--S? Forming a group of the form S-0-
Eight is also good.

The polyepoxy compound may be aliphatic, cycloaliphatic, aromatic or heterocyclic and may contain non-interfering substituents such as hydroxyl, alkyl, alkoxy, ester, acetal or ether groups. may be replaced. The most preferred polyepoxy compounds are polyglycidyl ethers of polyhydric phenols such as bisphenol A1 bisphenol F1 resorcinol, hydroquinone, 4.4''-diphenol, dihydroxydiphenyl sulfone, phenol, formaldehyde resin, cresol, formaldehyde resin.

Examples of other suitable polyepoxy compounds include:
Glycidyl ethers of polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, 1,4-butanediol, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methylendomethylenetetrahydrophthalic acid adipic acid,
Polyglycidyl esters of polyhydric carboxylic acids such as dimer acid, aniline, 4.4''-diaminodiphenyl esters, etc.
Glycidylamines derived from polyamines such as tan, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxy6-methylcyclohexyl methyl)- These include epoxidized polyolefins such as adipate, or epoxidized vegetable oils.

The method of the present invention performs similar curing treatment on systems containing pigments, plasticizers, fillers, and reactive diluents or solvents for monoepoxy compounds such as butyl glycidyl ether and phenyl glycidyl ether, as necessary. I can do it.

The curing temperature in the present invention is from 60 to 240°C, preferably from 10,077 to 180°C. The method of the present invention will be specifically explained below using Examples. Note that units are expressed by weight unless otherwise specified. Example 1 0.1 mol (6.8 g) of imidazole and 0.1 mol (6.8 g) of maleic acid.
1 mol (11.6 g) was placed in a glass reaction vessel, and the contents were heated to 130 g using an aluminum heating block equipped with a magnetic stirring device.
The mixture was heated at 3°C for 3 minutes, then 30 ml of acetone was added thereto, and then allowed to cool.

The thus precipitated crystals were separated and dried to give 13 g (yield 71%) of the crude target imidazolylsuccinic acid (M.p. > 200°C).
) was obtained. The crude crystals were further recrystallized with water to obtain 10 g of the desired product.

Example 2 0.1 mol (8.2 g) of 2-methylimidazole and 0.1 mol (11.6 g) of maleic acid were reacted in the same manner as in Example 1 to obtain the crude target product 2-methylimidazolyl succinic acid (M ．．
p. >200°C) 14g (yield 71%) was obtained.

The crystals were further recrystallized with water to obtain 10.5 g of the desired product. Example 3 0.1 mol (8.2 g) of 2-methylimidazole
and 0 moles of maleic acid (12.3g), DMF'12m
After heating and refluxing the three components of Example 1 for 1 hour using the apparatus of Example 1, the contents were dried under reduced pressure, 30 ml of acetone was added to the dried product, and the product was dried to obtain crude crystals (M.p. 〉2
00° C.) 18.4 g (yield 93%) was obtained. The crude crystals were further recrystallized with water to obtain the target product 2-methylimidazolyl succinic acid 1.
4.7g was obtained. Example 4 After heating and refluxing 0.1 mol (9.6 g) of 2-ethylimidazole, 0.1 mol (11.6 g) of maleic acid, and 20 ml of water in the apparatus of Example 1 for 2 hours, the contents was concentrated under reduced pressure, 20 ml of acetone was added to the residue, and the crystals were dried in a house to obtain 15.5 g (yield: 73%) of crude crystals (M.p. > 200° C.).

The crude crystals were further recrystallized with water to obtain 11.3 g of the target product, 2-ethylimidazolylsuccinic acid. Example 5 0.1 mole (22.2 g) of 2-undecylimidazole and 0.1 mole of maleic acid.
1 mol (11.6 g) was treated in the same manner as in Example 1 to obtain 32 g of crude crystals (M.p.l 86-188°C) (yield 95%).
I got it.

The crystals were re-crystallized with methanol to obtain the target product 2-undecylimidazolylsuccinic acid (M.p.21O~217C) 17.6
I got g. Example 6 2-heptadecyl imidazole 0.1 mol (30.6 g
) and 0.1 mol (11.6 g) of maleic acid were treated in the same manner as in Example 1 to give crude crystals (M.p.l 84-187°C) 4
0 g (yield 95%) was obtained.

The crystals were extracted and reconsolidated with ethanol using a Soxhlet extractor to obtain the target product 2-heptadecyl imidazolyl succinic acid (
M. p. 19O-197C) 28g were obtained.

Example 7 0.1 mol (8.2 g) of 4-methylimidazole
), maleic acid 0.1 mol (11.6 g), DMF'3
After heating and refluxing the three powders of ml using the apparatus of Example 1, 20 ml of acetone was added and the precipitated crystals were left to cool, and the precipitated crystals were dried in a house to obtain 13 g of crude crystals (M.p. > 200°C) ( A yield of 66% was obtained.

The crystals were further recrystallized with water to obtain 10.4 g of the target product 4-methylimidazolylsuccinic acid (M.p.>200°C). Example 8 0.1 mol of 2-ethyl-4-methylimidazole (11
g) and 0.1 mol (11.6 g) of maleic acid in Example 1.
Coarse crystals (M.p. 227-229°C)
16.5 g (yield 73%) was obtained.

The crystals were recrystallized with water to obtain 12.4 g of the desired product, 2-ethyl-4-methylimidazolylsuccinic acid (M.p.>230° C.). Example 9 0.1 mole (23.6 g) of 2-undecyl-4-methylimidazole and 0.1 mole of maleic acid (
11.6g) was treated in the same manner as in Example 1 to obtain crude crystals (M.
p. 154-15rC) 30g (yield 85%) was obtained.

The crystals were re-crystallized with methanol to obtain the target product 2-undecyl-4-methylimidazolyl succinic acid (M.p.l 87-18
9m C) 16.5g was obtained. Example 10 2-phenyl-4-methylimidazole 0.1 mol (1
5.8 g), 0.1 mol (11.6 g) of maleic acid, and 13 ml of water were heated under reflux for 3 hours using the apparatus of Example 1, then 20 ml of acetone was added, and after cooling, the precipitated crystals were filtered out. Dried crude crystals (M.p.l78-17CfC)
25 g (yield 91%) was obtained.

The crystals were further recrystallized with water to obtain the target product 2-phenyl-4-methylimidazolylsuccinic acid (M.p.2Ol~207C).
20g was obtained. Example 11 A case where various imidazolyl succinic acid compounds are used alone as a curing agent will be described.

Epoxy resin (product name: Epicoat 828, manufactured by Yuka Shell K.K.) 10 resin, imidazolyl-succinic acid compound, and colloidal silica for imparting thixotropic properties (product name:
Aerosil 300, Nippon Aerosil K. 2 parts (manufactured by K.) were passed through a three-roll machine to form a homogeneous mixture,
Its storage stability and gelation time were investigated.

The above formulation was stored at a temperature of 20° C., and the change in viscosity was measured. The end point was defined as the point when the viscosity reached the initial value, and the storage stability was defined as the number of days until the end point was reached.
The gelation time was determined as follows.

Place the sample on a hot iron plate preset at 150±0.5℃.
．． Place 7g of the sample and use a stainless steel spatula to remove the sample for about 20 x 3 hours.
Spread the sample to a size of 1, press the sample evenly at a speed of one reciprocation every 2 seconds, and knead the sample. Lift the spatula every now and then to find the time until no thread is drawn between the sample and the spatula. Ta,
These tests were as shown in the table below.

Example 12 2-ethylimidazolyl-succinic acid and 2-undecyl-4
- making a formulation using methylimidazolyl-succinic acid;
The physical properties of the cured product were also investigated at the same time.

The results of these tests are shown below. Example 13 A formulation example for adhesives using imidazolyl succinic acid to accelerate curing of dicyandiamide will be described.

M parts of Epicote 828, 3 parts of Epicote 834, 2 parts of a thixotropic agent (trade name Bentone 38, manufactured by National Red), 3 parts of extender pigment (trade name Mantal P, manufactured by Tsuchiya Kaolin), 6 parts of dicyandiamide, Two parts of the equivalent succinic acid were uniformly kneaded on a three-roll mill to obtain an adhesive formulation. These materials showed storage stability at 40'C for more than one month, rapidly cured at temperatures of 120°C or more, and exhibited strong adhesive strength.

Display the specifications of the formulation. Example 14 A formulation example for electrical casting using imidazolyl-succinic acid as an acid anhydride promoter will be described.

Claims (1)

[Claims] 1 Structural formula ▲ Numerical formula, chemical formula, table, etc. ▼ [However, in the formula, R_2 is a hydrogen atom, a methyl group, an ethyl group,
The residue R_4 selected from the group consisting of undecyl, heptadecyl and phenyl represents a hydrogen atom or a methyl group. ] An imidazolyl succinic acid compound. 2 Structural formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, in the formula, R_2 is a hydrogen atom, a methyl group, an ethyl group,
The residue R_4 selected from the group consisting of undecyl, heptadecyl and phenyl represents a hydrogen atom or a methyl group. ] There is a structural formula ▲ mathematical formula, chemical formula, table, etc., which is characterized by reacting an unsubstituted imidazole at the 1-position and maleic acid ▼ [However, in the formula, R_2 and R_4 are the same as above. ] A method for synthesizing an imidazolyl succinic acid compound. 3
Structural formula ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ [However, in the formula, R_2 and R_4 are the same as above. An epoxy resin curing method characterized by using an imidazolyl succinic acid compound represented by ] as a curing agent or curing accelerator.