Method for producing amine compound having isocyanurate ring, and amine compound

Abstract

To provide a method for producing an amine compound having an isocyanurate ring which is usable as a curing agent of an epoxy resin, is excellent in low temperature curability, and is excellent in coloration and heat-resistant colorability, and an amine compound having an isocyanurate ring.SOLUTION: There is provided a method for producing an amine compound represented by general formula (II) by reacting an amine precursor containing an isocyanurate ring represented by general formula (I) with an acid catalyst.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing an amine compound having an isocyanurate ring, and to an amine compound. [Background technology]

[0002] Various compounds having an isocyanurate ring are widely used in paints, adhesives, resists, etc. because of their good mechanical strength, dimensional stability, heat resistance, and electrical properties.

[0003] For example, Patent Document 1 proposes an epoxy resin composition containing 1,3,5-tris(2-carboxyethyl)isocyanurate (hereinafter referred to as CIC acid) as a curing agent. However, when CIC acid is used as a curing agent for epoxy resins, it has a drawback in that a temperature of 200° C. or higher is required to obtain a uniform cured product due to its high melting point and poor compatibility with epoxy resins.

[0004] Furthermore, as a curable epoxy resin composition, an epoxy resin composition for sealing optical semiconductors, which contains a compound obtained by reacting triglycidyl isocyanurate with a compound having a phenolic hydroxyl group, an acid anhydride curing agent, and a curing accelerator, has been proposed in Patent Document 2. However, these compositions also have the drawback of requiring a curing temperature of 150°C or higher.

[0005] In Patent Document 1, a triamine having an isocyanurate ring and represented by the following formula (VI) is synthesized in three steps using methyl nitrophenyl isocyanate as a starting material as an amine compound having an isocyanurate ring. However, although such aromatic amines have strong characteristics in terms of reactivity and resistance to thermal decomposition, they have problems in terms of low transparency, coloration, and heat yellowing resistance.

[0006] [ka]

[0007] Also, Patent Document 4 proposes an amine compound containing an isonurate ring. However, since the compound is not an active amino group but a sterically hindered piperidyl group, it cannot be used as a curing agent, although it is sufficiently effective as a light stabilizer.

[0008] [ka]

[0009] (In the formula, R1 represents a hydrogen atom, a methyl group, or an oxyl group.) [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 59-107742 [Patent Document 2] WO-2014-196515 [Patent Document 3] DE 10 2007 016 272 A1 [Patent Document 4] Patent Publication No. 6-293754 Summary of the Invention [Problem to be solved by the invention]

[0011] The problem to be solved by the present invention is to provide a method for producing an amine compound having an isocyanurate ring, which can be used as a curing agent for epoxy resins and has excellent low-temperature curing properties and excellent coloring and heat coloring resistance, and an amine compound having an isocyanurate ring. [Means for solving the problem]

[0012] As a result of intensive research, the inventors of the present invention have found that an amine compound represented by the following general formula (II) can be produced by reacting an amine precursor containing an isocyanurate ring and represented by the following general formula (I) in the presence of an acid catalyst, and have thus completed the present invention. That is, the present invention relates to the following [1] to [5]. [1] A method for producing an amine compound represented by the following general formula (II), comprising reacting an amine precursor containing an isocyanurate ring represented by the following general formula (I) with an acid catalyst.

[0013] [ka]

[0014] (R1's are each independently the same or different and each R2 is a hydrocarbon, and each R2 is a tertiary alcohol residue or a substituted benzyl alcohol residue.)

[0015] [ka]

[0016] (R1 are each independently the same or different hydrocarbons.)

[0017] [2] The method for producing an amine compound according to [1], wherein R1 in the formulas (I) and (II) is at least one of the following general formula (III):

[0018] [ka]

[0019] (In formula (III), the wavy line represents the bonding site with the nitrogen atom.)

[0020] The method for producing an amine compound according to [1] or [2], wherein the acid catalyst is selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid and p-toluenesulfonic acid.

[0021] The method for producing an amine compound according to any one of [1] to [3], wherein R2 in formula (I) is a tertiary alcohol residue represented by the following formula (IV) or a substituted benzyl alcohol residue represented by the following formula (V).

[0022] [ka]

[0023] (In the formula, R3 may be the same or different and is an organic group.)

[0024] [ka]

[0025] (In the formula, R4 is an organic group which may be the same or different.)

[0026] A compound represented by the following formula (II):

[0027] [ka]

[0028] (R1 are each independently the same or different hydrocarbons.) Effect of the Invention

[0029] The present invention provides a method for producing an amine compound containing an isocyanurate ring, which is useful as a curing agent for epoxy resins because it has excellent low-temperature curing properties and excellent coloring and heat-resistant coloring properties, and provides the amine compound. [Brief description of the drawings]

[0030] [Figure 1] 1 shows a GPC chart of Example 1. [Diagram 2] 1 shows the 1H-NMR chart of Example 1. [Diagram 3] 1 shows an IR spectrum of Example 1. [Figure 4] 1 shows a GPC chart of Example 2. [Diagram 5] 1H-NMR chart of Example 2 is shown. [Figure 6] 1 shows an IR spectrum of Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

[0032] The present invention is a method for producing an amine compound represented by the above general formula (II) by reacting an amine precursor containing an isocyanurate ring represented by the above general formula (I) with an acid catalyst. The amine precursor having an isocyanurate ring is obtained by reacting a polyisocyanate having an isocyanurate ring with a specific alcohol compound to obtain a carbamate amine precursor represented by the following general formula (I), which is then reacted with an acid catalyst to synthesize an amine compound.

[0033] [ka]

[0034] (R1's are each independently the same or different and each R2 is a hydrocarbon, and each R2 is a tertiary alcohol residue or a substituted benzyl alcohol residue.)

[0035] In the above formulas (I) and (II), R1 is preferably at least one of the following general formula (III).

[0036] [ka]

[0037] The wavy line in formula (III) is the bonding site to the nitrogen atom.

[0038] From the viewpoints of availability, heat resistance, and solvent solubility, the compounds having the structures of (A-2), (A-3), and (A-7) are preferred.

[0039] In the above formula (I), R2 is preferably a tertiary alcohol residue represented by the following formula (IV) or a substituted benzyl alcohol residue represented by the following formula (V).

[0040] [ka]

[0041] In the formula, R3 is an organic group which may be the same or different. R3 is preferably an alcohol residue derived from tert-butanol, 1-methylcyclohexanol-2-methyl-2-butanol, 2-methyl-2-pentanol, 3-quinuclidinyl benzilate, 3-methylpentanol, 2-methylisoborneol, 1-adamantanol, acetocyanohydrin, 1,3-adamantanediol, diacetone alcohol, triacetone alcohol, or triphenylmethanol.

[0042] [ka]

[0043] In the formula, R4 is an organic group which may be the same or different. R4 is not particularly limited as long as it is an electron-withdrawing group, and examples of R4 include alkoxy groups such as methoxy and ethoxy groups, hydroxyl groups, acetoxy groups, sulfonyl groups, formyl groups, nitro groups, azide groups, and cyano groups.

[0044] The reaction can be carried out without a solvent or with a solvent. The solvent that can be used is not particularly limited, and examples thereof include non-water-soluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone, but are not limited to these, and two or more of them may be used in combination. In addition to the non-water-soluble solvent, aprotic polar solvents can also be used in combination. For example, dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, etc. may be used in combination, and two or more of them may be used in combination.

[0045] The polyisocyanate having an isocyanurate ring is not particularly limited, and examples thereof include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (TMDI), lysine diisocyanate (LDI), 1,4-cyclohexane diisocyanate, isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate (H12MDI), norbornene diisocyanate (NBDI), xylylene diisocyanate (XDI), and tetramethylxylylene diisocyanate. Examples of the polyisocyanate include polyisocyanates obtained by trimerizing, by a known method, one or more oligomeric polyisocyanates, such as tris(isocyanate phenyl)thiophosphate, ...

[0046] For the synthesis of the amine precursor of the carbamate, a tertiary alcohol compound, 4-substituted benzyl alcohol material can be used.

[0047] Examples of tertiary alcohols include tert-butanol, 1-methylcyclohexanol-2-methyl-2-butanol, 2-methyl-2-pentanol, 3-quinuclidinyl benzilate, 3-methylpentanol, 2-methylisoborneol, 1-adamantanol, acetocyanohydrin, 1,3-adamantanediol, diacetone alcohol, triacetone alcohol, and triphenylmethanol.

[0048] As the substituted benzyl alcohol, for example, a benzyl alcohol having a structure represented by the following general formula (V) is preferable.

[0049] [ka]

[0050] In the formula, R4 is not particularly limited as long as it is an electron-withdrawing group, and examples thereof include alkoxy groups such as methoxy and ethoxy groups, hydroxyl groups, acetoxy groups, sulfonyl groups, formyl groups, nitro groups, azide groups, and cyano groups.

[0051] The carbamate reaction can be carried out without a catalyst or with a known catalyst, which is not particularly limited and includes, for example, metal catalysts such as butyltin dilaurate (DBTL), bismuth neodecanoate, and zinc octanoate, and basic catalysts such as triethylamine (TEA), imidazole, diazabicyclooctane (DABCO), and tertiary amines.

[0052] The carbamate reaction can be carried out at a reaction temperature of 40° C. to 150° C., more preferably in the range of 60° C. to 120° C. If the reaction temperature is too low, the reaction time may be long, and if the reaction temperature is too high, the reacted carbamate moiety may decompose.

[0053] A method for obtaining an amine compound from the amine precursor will be described. By using an acid catalyst for the amine precursor, the amine compound represented by the formula (I) above can be obtained. The acid catalyst is not particularly limited, but may be hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, Lewis acids such as aluminum chloride and zinc chloride, activated clay, acid clay, white carbon, zeolite, silica alumina, and other solid acids, acidic ion exchange resins, etc. These may be used alone or in combination of two or more. The amount of the acid catalyst used is 0.01 to 10.0 mol, preferably 0.05 to 5.0 mol, per 1.0 mol of the amine group produced. If the amount of catalyst is too small, the amine precursor may remain, whereas if the amount of catalyst is too large, purification after the reaction may become difficult.

[0054] The reaction for obtaining an amine compound from the carbamate reaction may be carried out through a known purification step after each reaction, or may be carried out continuously in one pot without going through a purification step.

[0055] In the reaction to obtain an amine compound from the amine precursor, the reaction can be carried out without a solvent or with a solvent. The solvent that can be used is not particularly limited, and examples thereof include non-water-soluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone, but are not limited thereto, and two or more of them may be used in combination. In addition to the non-water-soluble solvent, aprotic polar solvents can also be used in combination. For example, dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidone, etc. may be used in combination, and two or more of them may be used in combination.

[0056] The amine compound obtained by the above-mentioned manufacturing method is less colored and can be used as a curing agent. More specifically, the amine compound is excellent in low-temperature curing property, heat resistance, and heat yellowing resistance as a curing agent for epoxy resin. It is suitable for use as a sealant for organic EL elements, a sealant for high-brightness LEDs, and optical device components such as solar cells. EXAMPLES

[0057] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0058] <Gel Permeation Chromatography (GPC)> The weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated in terms of polystyrene using a polystyrene standard solution. GPC: HLC-8320GPC (Tosoh Corporation) Column: TSKgel SuperMultipreHZ-M Eluent: Tetrahydrofuran Column temperature: 40℃ Detection: RI (Differential Refractive Index Detector)

[0059] <Infrared absorption spectroscopy (IR)> Equipment: Shimadzu IRAffinity-1S <Amine value> The measurement was performed without using perchloric acid according to the method described in JIS K-7237, and the obtained value was taken as the amine equivalent in g / eq.

[0060] Synthesis Example 1 Into a four-neck flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen line were placed 208.0 g of toluene, 242.8 g of an isocyanurate modified product of isophorone diisocyanate (EVONIK's "VESTANAT T-1890 / 100", isocyanate group content 17.3% by mass), and 145.1 g (1.05 mol) of p-methoxybenzyl alcohol. The temperature was raised to 110°C while blowing nitrogen into the system, and the reaction was carried out at the same temperature for 10 hours. In the infrared spectrum, the characteristic absorption of the isocyanate group at 2250 cm was observed. -1It was confirmed that the absorption of 1H had completely disappeared, and the amount of isocyanate calculated from titration according to JIS K6806 was 0. The obtained solution was washed five times with water, and the solvent was distilled off to obtain 350 g (92% yield) of a white solid amine precursor (1) (R1 = the above formula (A-7)). The GPC chart of the obtained amine precursor is shown in Figure 1. (The amine precursor of formula (I) had a retention time of 15.090 min.) The number average molecular weight Mn was 1232 and the weight average molecular weight Mw was 1429 by GPC analysis. The 1H-NMR is shown in Figure 2, and the IR spectrum is shown in Figure 3. It was confirmed that a compound was produced from the IR spectrum and 1H-NMR.

[0061] Synthesis Example 2 Into a four-neck flask equipped with a stirrer, thermometer, condenser, and nitrogen line, 179.5 g of an isocyanurate modified product of hexamethylene diisocyanate (Tosoh Corporation's "Coronate HXLV", isocyanate group content 23.4% by mass), 81.4 g (1.1 mol) of tertiary butanol, and 11.2 g (0.1 mol) of triethylenediamine were added. The temperature was raised to 90°C while blowing nitrogen into the system, and the reaction was carried out at the same temperature for 16 hours. In the infrared spectrum, the characteristic absorption of the isocyanate group at 2250 cm was observed. -1 It was confirmed that the absorption of 1H had completely disappeared, and the amount of isocyanate calculated from titration according to JIS K6806 was 0. The obtained solution was washed five times with water, and the solvent was distilled off to obtain 221 g (87% yield) of a yellow viscous liquid amine precursor (2) (R1 = the above formula (A-3)). The GPC chart of the obtained amine precursor is shown in Figure 4. (The amine precursor of formula (I) had a retention time of 15.110 min.) The number average molecular weight Mn was 1200 and the weight average molecular weight Mw was 1436 by GPC analysis. The 1H-NMR is shown in Figure 5, and the IR spectrum is shown in Figure 6. It was confirmed that a compound was produced from the IR spectrum and 1H-NMR.

[0062] Example 1 To 100.0 g of the amine precursor (1) obtained in Synthesis Example 1, 150.0 g of toluene was added, and 57.8 g of methanesulfonic acid was added dropwise for 1 hour, followed by reaction at 60°C for 1 hour. After cooling, an aqueous sodium hydroxide solution was added until the pH reached 8. The precipitated solid was dissolved in the organic layer, washed five times with water, and the solvent was removed by concentration under reduced pressure. The amine equivalent of the obtained amine compound (1) was 222 g / eq (theoretical value: amine equivalent 217).

[0063] Example 2 To 100.0 g of the amine precursor (2) obtained in Synthesis Example 2, 84 g of sulfuric acid was added dropwise under ice cooling for 1 hour, and then the mixture was reacted at 60°C for 1 hour. After cooling, an aqueous sodium hydroxide solution was added until the pH reached 8. 150.0 g of diethyl ether was added to the resulting solution, and the solvent was removed by fractionating and concentrating the organic layer under reduced pressure. The amine equivalent of the resulting amine compound (2) was 180 g / eq (theoretical value: amine equivalent 154).

[0064] Comparative Example 1 A four-neck flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen line was charged with 273.0 g of toluene, 91.0 g of N-methylpyrrolidone, 242.8 g of an isocyanurate modified product of isophorone diisocyanate ("VESTANAT T-1890 / 100" manufactured by EVONIK, isocyanate group content 17.3% by mass), and 240 g of a 35% hydrochloric acid solution, and the mixture was stirred at 60°C for 1 hour and at 80°C for 2 hours, and an aqueous sodium hydroxide solution was added until the pH reached 8. The precipitated solid was dissolved in the organic layer, washed five times with water, and the solvent was removed by concentration under reduced pressure. The amine equivalent of the obtained amine compound (3) was 240 g / eq (theoretical value: amine equivalent 217).

[0065] Examples 3 to 4, Comparative Example 2 The amine compounds (1), (2), and (3) obtained above were mixed under the mixing conditions shown in the table to prepare resin liquids.

[0066] [Table 1]

[0067] Epoxy resin: RE-310S bisphenol A glycidyl ether (epoxy equivalent: 183g / eq) manufactured by Nippon Kayaku Co., Ltd.

[0068] <Curability> Each resin liquid was heated on a hot plate at 100° C., and the time until it lost its fluidity was measured. Less than 60 minutes was evaluated as ◯, and 60 minutes or more was evaluated as ×. <Transmittance, heat-resistant transmittance> Each resin liquid was poured into a 1 mm thick Teflon (registered trademark) mold and cured for 2 hours at 100° C., 2 hours at 120° C., and 3 hours at 180° C. The light transmittance of the cured resin was measured under the following conditions. Measurement equipment: Spectrophotometer U-3900H (Hitachi High-Tech Science) Measurement wavelength range: 00nm~800nm The transmittance at 400 nm of the obtained cured product and the transmittance at 400 nm after 1 hour at 230° C. were measured. A 400 nm transmittance of 60% or more was evaluated as ◯, and a transmittance of less than 60% was evaluated as x.

[0069] [Table 2]

[0070] From the above results, it was found that the amine compound of the present invention is excellent in low-temperature curing property, transmittance (coloration) and heat-resistant transmittance (heat-resistant coloration). Therefore, the amine compound of the present invention is useful as a curing agent for epoxy resins.

Claims

1. A method for producing an amine compound represented by the following general formula (II), comprising reacting an amine precursor containing an isocyanurate ring represented by the following general formula (I) with an acid catalyst. 【Chemistry 1】 (R １ are each independently the same or different hydrocarbons, R ２ represents a tertiary alcohol residue or a substituted benzyl alcohol residue. 【Chemistry 2】 (R １ are each independently a hydrocarbon which may be the same or different.

2. In the formulas (I) and (II), R １ The method for producing an amine compound according to claim 1, wherein the compound is one or more of the following general formula (III): 【Chemistry 3】 (The wavy line in formula (III) is the bonding site with the nitrogen atom.)

3. 2. The method for producing an amine compound according to claim 1, wherein the acid catalyst is selected from the group consisting of sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, trifluoroacetic acid and dodecylbenzenesulfonic acid.

4. R in formula (I) ２ is a tertiary alcohol residue represented by the following formula (IV) or a substituted benzyl alcohol residue represented by the following formula (V): 【Chemistry 4】 (In the formula R ３ are organic groups which may be the same or different. 【Chemistry 5】 (In the formula R ４ are organic groups which may be the same or different.

5. A compound represented by the following formula (II): 【Chemistry 6】 (R １ are each independently the same or different hydrocarbons.

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