JP2022023303A - Diamine composition production method - Google Patents

Abstract

To provide a production method of a diamine composition excellent in solubility in an epoxy resin.SOLUTION: In the diamine composition production method, a diamine composition comprising a compound represented by a specific structural formula is dissolved in a solvent (A) having a solubility parameter of 8.8 to 10.0 inclusive, and then brought into contact with a solvent (B) having a solubility parameter of 7.0 to 8.4 inclusive, so that the diamine composition is precipitated.SELECTED DRAWING: None

Description

The present invention relates mainly to a method for producing a diamine composition used as a curing agent for an epoxy resin composition used for a carbon fiber reinforced composite material.

A fiber-reinforced composite material that combines a reinforcing fiber and a matrix resin is widely used as a lightweight and high-strength material. Among them, carbon fiber reinforced composite materials using carbon fiber as reinforcing fiber are widely used in aerospace applications, sports applications, general industrial applications, etc. because they have high specific strength and specific elastic modulus.

As the matrix resin of the carbon fiber reinforced composite material, an epoxy resin having high adhesiveness to carbon fibers and mechanical properties of a cured product is often used. The epoxy resin is cured by a chemical reaction between a main agent having an epoxy group and a curing agent having a specific functional group. Various compounds such as a diamine compound, a dicyanamide compound, and an acid anhydride compound are used as a curing agent, and they are used alone or in combination depending on the intended use. Among the diamine compounds, aromatic diamine compounds having an aromatic ring in the molecule are used for many purposes, and for example, 3,3'-diaminodiphenyl sulfone has a long pot life and is preferably used (for example, Patent Document 1). reference). Further, in recent years, a fluorene amine compound having a bulky fluorene group among aromatic rings has been proposed as a curing agent that brings about a highly heat-resistant resin cured product due to its rigid structure (see, for example, Patent Document 2).

International Publication No. 1996/21695 International Publication No. 2016/089724

Since the above-mentioned fluorene amine compound generally has a high melting point and is not easy to be uniformly mixed with an epoxy resin, molding conditions and applications are limited (see, for example, Patent Document 2). Further, depending on the formulation and molding conditions, the aromatic diamine compound may not be completely dissolved in the epoxy resin and may remain undissolved in the cured resin, and the low toughness derived from the compound has been a problem. Therefore, an object of the present invention is to provide a method for producing a diamine composition having excellent solubility in an epoxy resin.

The present invention for solving the above problems has the following configurations.

That is, the first aspect of the method for producing a diamine composition of the present invention is a solvent (A) in which a diamine composition containing a compound represented by the general formula [1] has a solubility parameter of 8.8 or more and 10.0 or less. This is a method for producing a diamine composition, which precipitates a diamine composition by contacting it with a solvent (B) having a solubility parameter of 7.0 or more and 8.4 or less.

(However, in the formula, R ₁ and R ₂ are aromatic hydrocarbon groups having 6 to 16 carbon atoms, and these may be bonded to each other to form a ring. R ₃ and R ₄ are hydrogen atoms. , At least one selected from the group consisting of aliphatic hydrocarbon groups having 1 to 4 carbon atoms and halogen atoms).

The second aspect of the method for producing a diamine composition of the present invention is a method for producing a diamine composition containing a compound represented by the above general formula [1] and containing two or more different diamine compounds. A method for producing a diamine composition, which comprises the following steps (I) and (II).
(I) Two or more different diamine compounds including the compound represented by the general formula [1] were dissolved in a solvent (A) having a solubility parameter of 8.8 or more and 10.0 or less for each diamine compound. Later, the diamine compound is precipitated by contacting with the solvent (B) having a solubility parameter of 7.0 or more and 8.4 or less.
(II) The precipitates of the respective diamine compounds obtained in the steps (I) are mixed.

By using the diamine composition obtained by the production method of the present invention as an epoxy resin curing agent, an epoxy resin cured product having excellent toughness can be obtained.

The method for producing the diamine composition of the present invention will be described below.

(1) Diamine Composition In the present invention, the diamine composition means one kind of diamine compound or a mixture of two or more kinds of diamine compounds. When the diamine composition is a mixture of two or more kinds of diamine compounds, the mixing ratio is not limited and can be mixed at any ratio.

The diamine composition in the present invention contains a compound represented by the general formula [1], and may be a compound alone or a composition composed of only two or more kinds of compounds represented by the general formula [1], or other compounds. The composition may be contained. When the diamine composition contains a compound other than the compound represented by the general formula [1], the combination is not limited as long as it is a combination of the compound represented by the general formula [1] and a compound that does not react when the diamine composition is dissolved.

R ₁ and R ₂ in the above general formula [1] are aromatic hydrocarbon groups having 6 to 16 carbon atoms. Specific examples of R ₁ and R ₂ include a phenyl group, a fluorene group, an anthracene group and the like. R ₁ and R ₂ may be combined with each other to form a ring. Above all, in order to improve the heat resistance of the cured resin when the diamine composition obtained in the present invention is used as a curing agent for an epoxy resin, the compound represented by the general formula [1] is a compound represented by the following general formula [1]. It is preferably the compound shown in 2].

R ₃ and R ₄ in the general formula [1] and the general formula [2] are at least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms and a halogen atom. .. Specific examples of R ₃ and R ₄ include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a fluorine atom, a chlorine atom, a bromine atom and the like. Above all, from the viewpoint of solubility in the Eposi resin, it is preferable that either R ₃ or R ₄ is a hydrogen atom, and the other is an ethyl group.

From the viewpoint that the viscosity of the epoxy resin composition can be lowered when the diamine composition obtained in the present invention is used as an epoxy resin curing agent, the diamine composition is 3,3'-diaminodiphenyl sulfone and / or 4,4. '-It is preferable to contain diaminodiphenyl sulfone.

(2) Soldebrand In the method for producing the diamine composition of the present invention, the solvent (A) having a solubility parameter (hereinafter referred to as SP value) of 8.8 or more and 10.0 or less is a tetrahydrofuran (SP value 9.1, (Reference value), ether compounds such as 1,4-dioxane (SP value 10.0, literature value), methyl ethyl ketone (SP value 9.3, literature value), acetone (SP value 9.9, literature value) and the like Compound, ester compound such as ethyl acetate (SP value 9.1, literature value), methyl acetate (SP value 9.6, literature value), p-xylene (SP value 8.8, literature value), toluene (SP value) An aromatic hydrocarbon compound such as 8.9 (literature value), chloroform (SP value 9.3, literature value) and the like can be exemplified. From the viewpoint of solubility of the diamine composition, the lower limit of the SP value is preferably 8.9 or more, more preferably 9.1 or more. Further, the upper limit of the SP value is preferably 9.9 or less. Tetrahydrofuran, acetone and ethyl acetate are particularly preferable as the specific solvent. A solvent having an SP value outside the above range does not easily dissolve the diamine composition, so that the production efficiency of the diamine composition is significantly reduced.

Further, the solvent (A) having an SP value of 8.8 or more and 10.0 or less may be used alone, or a mixed solvent having an SP value of 8.8 or more and 10.0 or less by mixing two or more kinds of solvents. May be used as.

In the method for producing the diamine composition of the present invention, as the solvent (B) having an SP value of 7.0 or more and 8.4 or less, pentane (SP value 7.0, literature value), hexane (SP value 7.3, (Reference value), heptane (SP value 7.4, literature value), cyclohexane (SP value 8.2, literature value) and other hydrocarbon compounds, diethyl ether (SP value 7.4, literature value), methylisobutylketone (SP value 7.4, literature value) SP value 8.4, literature value) and the like can be exemplified. From the viewpoint of efficiently precipitating the diamine composition, the upper limit of the SP value is preferably 8.2 or less. As a specific solvent, cyclohexane, hexane, and pentane are particularly preferable. If a solvent having an SP value less than the lower limit of the above range is used, the difference in SP value from the solvent (A) is large, so that the solution in which the diamine composition is dissolved in the solvent (A) is brought into contact with the solvent (B). In some cases, they may be separated without being compatible with each other, and the production efficiency of the diamine composition is significantly reduced. Further, when a solvent having an SP value exceeding the upper limit of the above range is used, the diamine composition is difficult to precipitate, and it is difficult to efficiently obtain the diamine composition.

Further, the solvent (B) having an SP value of 7.0 or more and 8.4 or less may be used alone, or a mixture of two or more kinds of solvents and a SP value of 7.0 or more and 8.4 or less. It may be used as a solvent.

In the present invention, the solvent (A) having an SP value of 8.8 or more and 10.0 or less for dissolving the diamine composition, and the SP value of 7.0 or more and 8.4 or less to be contacted after dissolving the diamine composition. By appropriately selecting and combining the solvent (B), the diamine composition can be efficiently precipitated. From the viewpoint of efficiently precipitating the diamine composition, the difference between the SP values of the solvent (A) and the solvent (B) is preferably 0.9 or more as the lower limit and 2.9 or less as the upper limit. It is preferable to have. For example, acetone, tetrahydrofuran or ethyl acetate is used as the solvent (A) having an SP value of 8.8 or more and 10.0 or less, and cyclohexane, hexane or hexane is used as the solvent (B) having an SP value of 7.0 or more and 8.4 or less. A combination using heptan can be preferably exemplified.

The SP value (unit: (cal / cm ³ ) ^1/2 ) in the present invention is a document described on pages 688 to 694 of POLYMER HANDBOOK FORTH EDITION (written by EA GRULKE et al., JOHN WILEY & SONS). The value shall be used (the same applies to the SP value described as the “literature value” in the above-mentioned examples of the solvent (A) and the solvent (B)). In addition, if the SP value is not described, Polym. Eng. Sci. , 14, 2, 147-154 (1974), and the value calculated from the aggregation energy density of Fedors and the molar molecular weight is taken as the SP value. When two or more kinds of solvents are used, it is calculated by adding the product of each SP value and mole fraction.

(3) Method for Dissolving Diamine Composition In the method for producing a diamine composition of the present invention, a solvent (A) having an SP value of 8.8 or more and 10.0 or less is used for the diamine composition containing the compound represented by the general formula [1]. ), But here, dissolution means that the solution is not phase-separated into two or more layers and does not contain solid content. The presence or absence of phase separation can be analyzed using turbidity (JIS K0101 (1998)) or the like, and the presence or absence of solid content is determined by the diamine composition on the filter paper when filtered using a filter paper having a retained particle size of 1 μm. It can be confirmed that the solid derived from the substance does not remain substantially.

Examples of the method for dissolving the diamine composition in the solvent (A) include a method of mixing the diamine composition and the solvent (A), followed by stirring, ultrasonic irradiation, heating, and the like, as long as the diamine compound is dissolved. A method may be used, or a plurality of methods may be combined, but from the viewpoint of industrial feasibility, stirring is preferable, and stirring while heating is more preferable. The solution temperature at the time of dissolution cannot be uniquely determined because the preferable temperature differs depending on the type of the diamine composition and the solvent (A), but the lower limit thereof is usually 0 ° C. or higher, preferably 10 ° C. or higher. Yes, more preferably 20 ° C. or higher. Further, the upper limit thereof is preferably 300 ° C. or lower, more preferably 200 ° C. or lower, and more preferably 100 ° C. or lower from the viewpoint of industrial feasibility. In order to prevent evaporation of the solvent during heating, it is preferable to connect a cooling tube or the like to the dissolution tank to reflux.

As will be described later, in order to efficiently precipitate the diamine composition, the concentration at which the diamine composition is dissolved in the solvent (A) is preferably 70% or more, preferably 80% or more of the solubility of the diamine composition. It is more preferable, and it is particularly preferable that the content is 90% or more, and the higher the concentration is, the more preferable it is in order to obtain a diamine composition in a high yield.

In the present invention, the solubility means the concentration of the saturated solution. Solubility is measured by adding a solute to 100 g of solvent, stirring for 10 minutes to prepare a saturated solution, and analyzing the solution obtained by solid-liquid separation by filtration or centrifugation by liquid chromatography. be able to.

(4) Precipitation Method of Diamine Composition In the method for producing a diamine composition of the present invention, the SP value of the diamine composition solution obtained by the method described in (3) above is 7.0 or more and 8.4 or less. The diamine composition can be precipitated by contacting the solvent (B). In order to obtain a precipitate having a uniform form, it is preferable to stir the inside of the tank when the solvent (B) is brought into contact with the solution of the diamine composition.

A known method may be used for stirring. In particular, in the case of stirring with a stirring blade, the stirring speed is preferably 50 rpm to 1,200 rpm, more preferably 100 rpm to 1,000 rpm, and further preferably 200 rpm to 800 rpm, although it depends on the shape of the stirring blade. Yes, and particularly preferably 300 to 500 rpm.

Specific examples of the stirring blade include a propeller type, a paddle type, a flat paddle type, a turbine type, a double cone type, a single cone type, a single ribbon type, a double ribbon type, a screw type, and a helical ribbon type. , The system is not limited to these as long as the shearing force can be sufficiently applied to the system. Further, in order to perform efficient stirring, a baffle plate or the like can be installed in the tank.

As a method of contacting the solvent (B) with the solution of the diamine composition obtained under the conditions described in (3) above, a method of adding the solvent (B) to the solution of the diamine composition may be used, or the solvent (B) may be added. ) May be added to the solution of the diamine composition, but the method of adding the solvent (B) to the solution of the diamine composition is preferable.

Examples of the method of adding the solvent (B) include a method of adding the solvent (B) all at once, a method of adding the solvent continuously, and a method of adding the solvent intermittently. In order to obtain a uniform precipitate, it is preferable that the solution concentration becomes uniform rapidly after the solvent (B) is added. Therefore, a method of continuously or intermittently adding the solvent (B) at a constant rate over a long period of time is preferable. .. Specific examples thereof include a method using a liquid feeding pump, a self-weight feeding liquid, a spray, and the like, and any method may be used as long as the diamine composition is precipitated.

The time required to add the solvent (B) at a constant rate varies depending on the type and concentration of the diamine composition contained in the solution and the type of the solvent (A), so it cannot be uniquely determined, but it is usually 1 minute or more. Yes, preferably 5 minutes or more. The upper limit is not particularly limited, but is 50 hours or less, preferably 20 hours or less, more preferably 10 hours or less, and particularly preferably 1 hour or less. If carried out within this range, it is easy to obtain a precipitate having a uniform form without forming a lump. If it is carried out for a longer time, it is unrealistic when considering industrial implementation.

The amount of the solvent (B) to be brought into contact with the solution of the diamine composition obtained under the conditions described in (2) and (3) is the type and concentration of the diamine composition contained in the solution, the solution temperature, and the solvent ( Although it cannot be uniquely determined because it differs depending on the type of A), the amount may be sufficient for the diamine composition to precipitate, and the lower limit is 0.1 times or more with respect to the volume of the diamine composition solution. Can be exemplified, preferably 1 time or more, and particularly preferably 3 times or more. The upper limit is not particularly limited, but is preferably 50 times or less, and more preferably 10 times or less.

The temperature of the diamine composition solution when the solvent (B) is brought into contact with the diamine composition solution obtained under the conditions described in (3) above may be room temperature, and even if the solution is heated, it is cooled. You may. The temperature of the solution cannot be uniquely determined because it varies depending on the type and concentration of the diamine composition contained in the solution and the type of the solvent (A), but usually 0 ° C. or higher can be exemplified, and preferably 10 ° C. or higher. More preferably, it is 20 ° C. or higher. Further, the upper limit thereof is preferably 300 ° C. or lower, more preferably 200 ° C. or lower, and more preferably 100 ° C. or lower from the viewpoint of industrial feasibility. In order to prevent evaporation of the solvent during heating, it is preferable to connect a cooling tube or the like to the precipitation tank to reflux.

Stirring may be continued after the addition of the solvent (B) is completed, and the stirring time is not limited.

In the method for producing a diamine composition of the present invention, the steps described in (3) and (4) are preferably carried out under normal pressure from the viewpoint of industrial feasibility.

Further, in the method for producing a diamine composition of the present invention, the steps described in (3) and (4) can be carried out in the atmosphere, but the dissolution tank is preferably filled with an inert gas. Specifically, nitrogen, helium, argon and carbon dioxide can be exemplified, and nitrogen and argon are preferable.

(5) Solid-Liquid Separation and Drying of Diamine Composition In the method for producing a diamine composition of the present invention, the diamine composition precipitated by the method according to (4) above can be solid-liquid separated by a known method. can. Examples of the method include gravity filtration, vacuum filtration, pressure filtration, centrifugation, and centrifugal filtration. When using filter paper, filter cloth, metal mesh, glass filter, etc. for gravity filtration, vacuum filtration, and pressure filtration, a diamine composition can be efficiently obtained by selecting a material having an appropriate retention particle size. ..

The solid-liquid separated diamine composition can be efficiently removed from the solvent (A) by washing with the solvent (B) or the like, if necessary.

Further, the diamine composition obtained by solid-liquid separation can be dried by a known method. Examples of the method include air drying, heat drying, and vacuum drying. When heating, it is preferable to carry out at a temperature equal to or lower than the melting point of the diamine composition.

(6) Method of Mixing Precipitates In the method for producing a diamine composition of the present invention, a diamine composition can also be produced by a method including the following steps (I) and (II).
(I) For two or more different diamine compounds including the compound represented by the general formula [1], each diamine compound is dissolved in the solvent (A) and then contacted with the solvent (B) to bring the diamine compound. Is deposited.
(II) The precipitates of the respective diamine compounds obtained in the steps (I) are mixed.

In the step (I), the two or more different diamine compounds including the compound represented by the general formula [1] include only two or more kinds of compounds represented by the general formula [1] and other compounds. You may.

Each diamine compound in step (I) can be produced under the same conditions as in (2) to (5) above.

When mixing the precipitate of the diamine compound in the step (II), a known method may be used, and if necessary, the mixture may be mixed while being pulverized. Examples of the method include a method using a container rotary type mixer, a method using a stirring type mixer, and a method using a mortar.

(7) Applications There are no restrictions on the applications of the diamine composition obtained in the present invention, but it can be preferably used as a curing agent for epoxy resins or as an amine raw material for polyimide.

When the diamine composition obtained in the present invention is used as a curing agent for an epoxy resin, it may be pulverized and used by a known method. As the method, a method using a mortar, a roller mill, a jet mill, a hammer mill, a vibration mill and the like can be exemplified.

Further, when preparing an epoxy resin composition using the diamine composition obtained in the present invention, the type of epoxy resin used is not limited, and two or more types of epoxy resin may be contained. Further, a curing agent, a reaction accelerator, a filler and the like other than the diamine composition obtained in the present invention may be combined. From the viewpoint of the strength and heat resistance of the cured resin, the total number of active hydrogens (H) of all the curing agent compositions including the diamine composition obtained in the present invention and the total number of epoxy groups in all the epoxy resin components ( It is preferable that the content satisfies the ratio of E), that is, the so-called H / E in the range of 0.80 or more and 1.10 or less.

In the method for producing a diamine composition of the present invention, a diamine composition having excellent solubility in an epoxy resin can be obtained, and when the obtained diamine composition is used as an epoxy resin curing agent, high heat resistance of the cured product can be obtained. Since it is possible to improve the toughness while maintaining it, it is suitable as a method for producing a curing agent for an epoxy resin used as a matrix resin for a carbon fiber reinforced composite material.

Hereinafter, the method for producing the diamine composition of the present invention will be described more specifically by way of examples. The production method and evaluation method of the diamine compound and the resin raw material used in the examples are shown below.

(Diamine compound)
・ 3,3'-DAS (3,3'-diaminodiphenyl sulfone, manufactured by Konishi Chemical Industry Co., Ltd.)
FMEA (9,9-bis (3-ethyl-4-aminophenyl) fluorene, synthesized by the method described below)
9-Fluorenone (manufactured by Tokyo Chemical Industry Co., Ltd.) 14.4 g (0.08 mol), 2-ethylaniline (Tokyo Chemical Industry Co., Ltd.) in a four-necked flask equipped with a thermometer, dropping funnel, condenser and stirrer. (Manufactured by Tokyo Chemical Industry Co., Ltd.) 115.6 g (1.05 mol) and 57.6 g of toluene (4 mass times / 9-fluorenone) were charged. The solution was cooled to 15 ° C. or lower under stirring with a nitrogen purge, and 25.0 g (0.24 mol) of 35% hydrochloric acid was added dropwise. After the heat generation had subsided, the temperature was raised to 90 to 110 ° C., and the water and toluene in the system were azeotropically heated. After the distillation has subsided, 14.4 g (1 mass times / 9-fluorenone) of toluene is further added, and the liquid temperature is raised to 130 to 140 ° C. while azeotropically boiling the water and toluene in the system again. A condensation reaction was carried out by aging with stirring for 66 hours.

After the condensation reaction, the reaction solution was cooled, and 56.4 g of 17% by mass caustic soda water was added at 50 ° C. to neutralize the reaction solution. The aqueous phase was discharged from the lower layer, and 21.6 g of isopropanol and 10.8 g of water were added to the obtained oil phase to crystallize 9,9-bis (3-ethyl-4-aminophenyl) fluorene. The obtained slurry was cooled to room temperature and solid-liquid separation was performed. The obtained cake was rinsed with 21.6 g of 2-propanol to obtain crude 9,9-bis (3-ethyl-4-aminophenyl) fluorene. This was refluxed with 43.2 g of toluene for 1 hour, cooled to room temperature, filtered, and the obtained cake was rinsed with 7.2 g of toluene. This was vacuum dried overnight at a temperature of 60 ° C. and a reduced pressure of 0.01 kPa or less. 25.4 g (yield 78% / 9-fluorenone) of 9,9-bis (3-ethyl-4-aminophenyl) fluorene was obtained. The chemical purity by liquid chromatography analysis was 99.2%.

(solvent)
・ Tetrahydrofuran (SP value 9.1, literature value, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.)
・ Cyclohexane (SP value 8.2, literature value, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.)
・ Acetone (SP value 9.9, literature value, manufactured by Sanwa Chemical Industry Co., Ltd.)
-N-Methylpyrrolidone (SP value 11.2, calculated value, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.).

(Amine type epoxy resin)
・ Pentane (SP value 7.0, literature value, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.)
-MY-721 (Tetraglycidyldiaminodiphenylmethane, manufactured by Huntsman).

(Manufacturing of diamine composition)
(Example 1)
In a 1000 ml eggplant flask, add 25.0 g of FMEA as a diamine composition and 68 mL of tetrahydrofuran as a solvent (A) having an SP value of 8.8 or more and 10.0 or less, and irradiate with ultrasonic waves until the solution becomes transparent. Stirring was performed. Then, while continuing stirring at 300 rpm, 272 mL of cyclohexane was added dropwise over 9 minutes as the solvent (B) having an SP value of 7.0 or more and 8.4 or less. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained wet cake was vacuum dried at a temperature of 40 ° C. for 2 hours to obtain 21.1 g of a powdery white solid.

(Example 2)
In a 1000 ml eggplant flask, add 25.1 g of FMEA as a diamine composition, 14.9 g of 3,3'-DAS, and 90 mL of tetrahydrofuran as a solvent (A), and in a water bath at 40 ° C. until the solution becomes transparent. Was stirred in. Then, while continuing stirring at 300 rpm, 360 mL of cyclohexane as the solvent (B) was added dropwise over 36 minutes. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained cake was vacuum dried at a temperature of 40 ° C. for 3 hours to obtain 35.3 g of a powdery white solid.

(Example 3)
In a 1000 ml eggplant flask, 28.7 g of FMEA as a diamine composition, 11.3 g of 3,3'-DAS, and 80 mL of tetrahydrofuran as a solvent (A) are added, and ultrasonic irradiation and stirring are performed until the solution becomes transparent. Was done. Then, while continuing stirring at 300 rpm, 320 mL of cyclohexane as the solvent (B) was added dropwise over 32 minutes. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained cake was vacuum dried at room temperature for 3 hours to obtain 38.0 g of a powdery white solid.

(Example 4)
In a 1000 ml 4-necked flask, 25.0 g of FMEA as a diamine compound and 75 mL of tetrahydrofuran as a solvent (A) were added, and ultrasonic irradiation and stirring were performed until the solution became transparent. Then, while continuing stirring at 300 rpm, 300 mL of cyclohexane as the solvent (B) was added dropwise over 30 minutes. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained cake was vacuum dried at room temperature for 3 hours to obtain 20.2 g of a powdery white solid (C). On the other hand, 25.0 g of 3,3'-DAS as a diamine compound and 178 mL of tetrahydrofuran as a solvent (A) were added to another 1000 ml eggplant flask, and ultrasonic irradiation was performed until the diamine compound was completely dissolved. Stirring was performed. Then, 712 mL of cyclohexane as the solvent (B) was added dropwise over 35 minutes while continuing stirring at 300 rpm. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained cake was vacuum dried at room temperature for 3 hours to obtain 19.1 g of a powdery white solid (D). 18.0 g of the white solid (C) and 10.7 g of the white solid (D) were mixed using a mortar.

(Example 5)
In a 1000 ml eggplant flask, add 25.0 g of FMEA as a diamine composition and 300 mL of acetone as a solvent (A) having an SP value of 8.8 or more and 10.0 or less, and irradiate with ultrasonic waves until the solution becomes transparent. Stirring was performed. Then, while continuing stirring at 300 rpm, 1.2 L of pentane was added dropwise over 30 minutes as the solvent (B) having an SP value of 7.0 or more and 8.4 or less. The suspension obtained after the total amount of cyclohexane was added was filtered under reduced pressure. The obtained wet cake was vacuum dried at a temperature of 40 ° C. for 2 hours to obtain a powdery white solid.

(Comparative Example 1)
14.9 g of 3,3'-DAS and 25.1 g of FMEA were mixed using a mortar.

(Comparative Example 2)
In a 1000 ml 4-neck flask, 25.1 g of FMEA as a diamine composition, 14.9 g of 3,3'-DAS, and 500 mL of water (SP value: 23.4, literature value) as a solvent were added and stirred. However, it did not dissolve and became cloudy.

(Comparative Example 3)
In a 1000 ml 4-neck flask, add 25.1 g of FMEA as a diamine composition, 14.9 g of 3,3'-DAS, and 90 mL of tetrahydrofuran as a solvent (A), and in a water bath at 40 ° C. until the solution becomes transparent. Was stirred in. Then, 360 mL of acetone was added dropwise over 36 minutes while continuing stirring at 300 rpm. No solids were deposited by the time the total amount of acetone had been added.

(Comparative Example 4)
In a 1000 ml 4-neck flask, 15.0 g of FMEA, 15.0 g of 3,3'-DAS and 300 mL of N-methylpyrrolidone were added as a diamine composition, and the mixture was stirred until the solution became transparent. Then, 300 mL of cyclohexane was added dropwise over 10 minutes while continuing stirring at 300 rpm. The solution separated into two layers and the diamine composition did not precipitate.

(Preparation of epoxy resin composition and preparation of resin cured plate)
(Example 6)
The diamine composition obtained in Example 1 was added to MY-721 heated in an oven set at 80 ° C. and mixed with a spatula. The mixing ratio of MY-721 and the diamine composition is the ratio of the total number of active hydrogens (H) of the diamine composition to the total number of epoxy groups (E) in all the epoxy resin components, that is, H / E is 1/1. I tried to be. The epoxy resin composition was prepared by stirring the mixture with a spatula while heating it in an oven. The obtained epoxy resin composition was defoamed in vacuum and then injected into a mold set to a thickness of 2 mm by a 2 mm thick “Teflon®” spacer. It was cured at a temperature of 180 ° C. for 2 hours to obtain a resin cured plate having a thickness of 2 mm.

(Examples 7 to 9, Comparative Examples 5 to 7)
The epoxy resin composition was prepared and the resin cured plate was prepared in the same manner as in Example 5. The diamine composition (F) used is as shown in Table 2 (see Table 1 as appropriate).

(Undissolved diamine composition in the resin curing plate)
An optical microscope (VHX-5000) was placed near the center of the obtained 2 mm resin cured plate under a black background.
It was magnified 400 times and photographed by KEYENCE CORPORATION. The number of particles having a major axis of 150 μm or more per 50 mm ³ of the cured resin plate was counted at three places on the image of the cured resin plate, and the average value was calculated.

(Measurement of bending and bending of epoxy resin hardened plate)
A test piece having a width of 10 mm and a length of 60 mm was cut out from the vicinity of the center of the resin cured plate, and for each test piece, a three-point bending with a span spacing of 32 mm was measured, and the bending deflection amount was measured according to JIS K7171-1994.

(Measurement of glass transition temperature (Tg) of epoxy resin cured plate)
A test piece having a width of 12.7 mm and a length of 45 mm was cut out from the vicinity of the center of the resin cured plate. The test piece was heated in an oven at 200 ° C. for 2 hours and then allowed to cool to room temperature, and DMA measurement (ARES, manufactured by TA Instruments) was performed at a heating rate of 5 ° C./min. In the graph of storage elastic modulus and temperature obtained by the measurement, the temperature at the intersection of the tangent line drawn in the glass region and the tangent line drawn in the glass transition region was defined as the glass transition temperature (Tg).

The diamine composition obtained by the method for producing a diamine composition of the present invention has excellent solubility in an epoxy resin, and when used as an epoxy resin curing agent, a cured product having high heat resistance and high toughness can be obtained. Further, if the epoxy resin composition using the diamine composition obtained by the method for producing the diamine composition of the present invention is used as the matrix resin of the fiber reinforced composite material, it is possible to provide a fiber reinforced composite material having high heat resistance and high strength. Become. As a result, the application of fiber-reinforced composite materials to aircraft and automobile applications will progress, and it is expected that further weight reduction will contribute to improved fuel efficiency and reduction of global warming gas emissions. Further, this epoxy resin composition makes it possible to obtain a cured epoxy resin having high heat resistance and high strength, which can be suitably used for electronic materials such as semiconductor encapsulants.

The diamine composition obtained by the method for producing a diamine composition of the present invention can be expected to obtain a film or fiber having high heat resistance and high strength by using it as a diamine raw material such as aromatic polyamide and polyimide.

Claims (10)

A diamine composition containing a compound represented by the general formula [1] is dissolved in a solvent (A) having a solubility parameter of 8.8 or more and 10.0 or less, and then a solvent having a solubility parameter of 7.0 or more and 8.4 or less. A method for producing a diamine composition, which precipitates a diamine composition by contacting (B).

(However, in the formula, R ₁ and R ₂ are aromatic hydrocarbon groups having 6 to 16 carbon atoms, and these may be bonded to each other to form a ring. R ₃ and R ₄ are hydrogen atoms. , At least one selected from the group consisting of aliphatic hydrocarbon groups having 1 to 4 carbon atoms and halogen atoms.) The method for producing a diamine composition according to claim 1, wherein the diamine composition comprises 3,3'-diaminodiphenyl sulfone and / or 4,4'-diaminodiphenyl sulfone. A method for producing a diamine composition containing a compound represented by the general formula [1] and containing two or more different diamine compounds, which comprises the following steps (I) and (II).
(I) Two or more different diamine compounds including the compound represented by the general formula [1] were dissolved in a solvent (A) having a solubility parameter of 8.8 or more and 10.0 or less for each diamine compound. Later, the diamine compound is precipitated by contacting with the solvent (B) having a solubility parameter of 7.0 or more and 8.4 or less.
(II) The precipitates of the respective diamine compounds obtained in the steps (I) are mixed.

(However, in the formula, R ₁ and R ₂ are aromatic hydrocarbon groups having 6 to 16 carbon atoms, and these may be bonded to each other to form a ring. R _{3 and} R ₄ are hydrogen atoms. , At least one selected from the group consisting of aliphatic hydrocarbon groups having 1 to 4 carbon atoms and halogen atoms.) The method for producing a diamine composition according to claim 3, wherein the diamine composition comprises 3,3'-diaminodiphenyl sulfone and / or 4,4'-diaminodiphenyl sulfone. The method for producing a diamine composition according to any one of claims 1 to 4, wherein the diamine compound represented by the general formula [1] is the diamine compound represented by the general formula [2].

(However, in the formula, R ₃ and R ₄ are at least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and a halogen atom.) The method for producing a diamine composition according to any one of claims 1 to 5, wherein at least one of R ₃ and R ₄ is a methyl group or an ethyl group. The solvent (A) is at least one selected from the group consisting of an ether compound having a solubility parameter of 8.8 or more and 10.0 or less, a ketone compound, a carboxylic acid ester compound, an aromatic hydrocarbon compound and a halogenated hydrocarbon compound. The method for producing a hydrocarbon composition according to any one of claims 1 to 6, which is a compound. The seventh aspect of claim 7, wherein the solvent (A) is at least one compound selected from the group consisting of tetrahydrofuran, 1,4-dioxane, methyl ethyl ketone, acetone, ethyl acetate, methyl acetate, p-xylene, toluene and chloroform. Method for producing a diamine composition. Any of claims 1 to 8, wherein the solvent (B) is at least one compound selected from the group consisting of an aliphatic hydrocarbon compound having a solubility parameter of 7.0 or more and 8.4 or less, an ether compound, and a ketone compound. The method for producing a diamine composition according to. The method for producing a diamine composition according to claim 9, wherein the solvent (B) is at least one compound selected from the group consisting of pentane, hexane, heptane, cyclohexane, diethyl ether and methyl isobutyl ketone.