JP2022087932A - Amine-based curing agent and use thereof - Google Patents

Abstract

To provide a curing agent (MOCA replacement) having a balance of pot life and curing properties equivalent to that of MOCA (3, 3'-dichloro-4,4'-diaminodiphenylmethane).SOLUTION: An amine-based curing agent for manufacturing polyurethane is used which includes 4,4-methylenebis(2-bromoaniline).SELECTED DRAWING: None

Description

The present invention relates to an amine-based curing agent used in polyurethane production.

Polyurethane is widely used in the fields of soft foam such as cushions, hard foam such as heat insulating materials, paints, synthetic leather, adhesives, sealants, textile products, waterproof materials, flooring materials, all-weather paving materials, etc. It is an industrial product that is indispensable to the space. 4,4'-Methylenebis (2-chloroaniline) (hereinafter abbreviated as MOCA) is often used as a curing agent for urethane resin used for waterproof materials, floor materials, all-weather pavement materials, etc. (for example, patent). Document 1). Although MOCA has an excellent balance of performance as a curing agent, it has been found to be carcinogenic to humans and has been designated as a Class I Specified Chemical Substance, so switching is accelerating in Japan as well. Against this background, an amine-based curing agent as an alternative to MOCA is strongly desired, but a material that is satisfactory in terms of performance has not been obtained. For example, as an alternative to MOCA, diethyltoluenediamine, a composition of an amine compound different from diethyltoluenediamine, and the like are disclosed (for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 8-34829 JP-A-2005-58918

However, diethyltoluenediamine has a problem that it is difficult to handle by itself because it is more reactive and has a shorter pot life than MOCA. Further, in the formulation in which an amine compound having low reactivity is blended with diethyltoluenediamine, a pot life longer than that of MOCA can be secured, but there is a problem that the curing property is deteriorated because the time required for curing is long. The present invention is to provide a curing agent (MOCA substitute) having a balance of pot life and curing characteristics equivalent to MOCA.

As a result of diligent studies to solve the above problems, the present inventors have found a curing agent containing 4,4'-methylenebis (2-bromoaniline). That is, the present invention relates to the use of 4,4'-bis (2-bromoaniline).

The curing agent containing 4,4'-methylenebis (2-bromoaniline) of the present invention has a remarkable pot life (pot life) longer than MOCA and is superior in curing (curing property) to MOCA. It works. Therefore, according to the present invention, it is possible to provide a curing agent having better workability and workability than MOCA.

Hereinafter, the present invention will be specifically described.

The present invention relates to an amine-based curing agent for producing polyurethane, which comprises 4,4'-methylenebis (2-bromoaniline).

4,4'-Methylenebis (2-bromoaniline) can be produced by a known synthetic method. For example, a method of condensing 2-bromoaniline and formaldehyde (for example, Reference 1: J. Chem. Pharm. Res., 2012, 4, 4260), a method of synthesizing 4,4-methylenebis (aniline) as a raw material (for example). For example, Reference 2: International Journal of Chemical Studies 2016; 4 (4): 178-181) and the like are known. Of these, the method of condensing 2-bromoaniline and formaldehyde by-produces oligomers and complicates the purification operation. Therefore, in order to obtain a high-purity product of 4,4'-methylenebis (2-bromoaniline) 4, A method of brominating and synthesizing 4'-methylenebis (aniline) as a raw material is desirable.

The amine-based curing agent for producing polyurethane, which comprises 4,4'-methylenebis (2-bromoaniline) of the present invention, may contain a small amount of impurities. Examples of the impurities include raw materials for producing 4,4'-methylenebis (2-bromoaniline) (2-bromoaniline, 4,4-methylenebis (aniline), etc.) and by-products (polymers of 2-bromoaniline and formarin). , 4,4'-diamino-2-bromodiphenylmethane, 4,4'-diamino-2,2', 6'-tribromodiphenylmethane, 4,4'-methylenebis (2,6-dibromoaniline), etc.) be able to.

The amine-based curing agent for polyurethane production containing 4,4'-methylenebis (2-bromoaniline) can be used as an amine-based curing agent in polyurethane resin production according to a generally known production formulation. That is, a polyurethane resin can be obtained by reacting an amine-based curing agent for producing polyurethane containing at least 4,4'-methylenebis (2-bromoaniline) with an isocyanate compound.

The amine-based curing agent for polyurethane production containing 4,4'-methylenebis (2-bromoaniline) of the present invention may contain other amine-based curing agents, but it does not necessarily have to be contained. Instead, it may be an amine-based curing agent for producing polyurethane, which is composed of 4,4'-methylenebis (2-bromoaniline).

The amine-based curing agent other than 4,4'-methylenebis (2-bromoaniline) is not particularly limited, but for example, MOCA, diethyltoluenediamine, 2,2', 3,3'-tetrachloro-. 4,4'-Diaminodiphenylmethane, 3,3'-diethyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dichloro-3,3', 5,5'-tetraethyl-4 , 4'-diaminodiphenylmethane, 2,2'-dichloro-5,5'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylmethane, 1,2- Bis (2-aminophenylthio) ethane, 2-ethyl-4,6-dimethyl-1,3-benzenediamine, 4-methyl-2,6-bis (methylthio) -1,3-benzenediamine, 3,5 Aromatic primary amines such as -diamino-4-chloro-methylpropyl benzoate, 2,4-diaminotoluene, and 2,6-diaminotoluene, 4,4'-methylenebis (N-sec-butylaniline), 4 , 4'-Methylenebis (N-methylaniline) and other aromatic secondary amines can be exemplified.

When the amine-based curing agent for polyurethane production contains an amine-based curing agent other than 4,4'-methylenebis (2-bromoaniline), the 4,4'-methylenebis (2-bromoaniline) in the curing agent. The content is preferably 30 to 99% by weight in terms of excellent curability balance. More preferably, it is 50 to 99% by weight. It is more preferably 65 to 99% by weight.

Regarding the amine-based curing agent for polyurethane production containing 4,4'-methylenebis (2-bromoaniline) of the present invention, further, a polyol compound, a plasticizing agent, an amine catalyst (tertiary amine compound), an organic metal catalyst, and a carboxyl. It can be used in the production of polyurethane resin as a curing agent composition for polyurethane production by containing an acid metal salt catalyst, a quaternary ammonium salt catalyst, a foaming agent, a foam stabilizer, a flame retardant, or other additives. can.

The above-mentioned polyol compound is not particularly limited, but for example, conventionally known polyhydric alcohols, polyether polyols, polyester polyols, polymer polyols, flame-retardant polyols such as phosphorus-containing polyols and halogen-containing polyols, and the like. Can be mentioned. These polyols can be used alone or in combination as appropriate.

The polyhydric alcohol is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, glycerin, 1,4-butanediol, trimethylolpropane, and pentaerythritol.

The polyether polyol is not particularly limited, but for example, a compound having at least two or more active hydrogen groups (specifically, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol and the like). Polyhydric alcohols, amines such as ethylenediamine, alkanolamines such as ethanolamine and diethanolamine are exemplified), and alkylene oxides (specifically, ethylene oxide and propylene oxide) are exemplified. The one manufactured by the addition reaction with (1) is mentioned.

The polyester polyol is not particularly limited, but for example, one obtained from the reaction of dibasic acid and glycol, a by-product during nylon production, trimethylolpropane, a by-product of pentaeristol, and the like. Examples thereof include by-products of phthalic acid-based polyesters, polyester polyols obtained by treating and inducing by-products, and the like.

The polymer polyol is not particularly limited, but for example, the polyether polyol and an ethylenically unsaturated monomer (for example, butadiene, acrylonitrile, styrene, etc.) are used in the presence of a radical polymerization catalyst. Examples thereof include the reacted polymer polyol.

The flame-retardant polyol is not particularly limited, but for example, it contains a phosphorus-containing polyol obtained by adding an alkylene oxide to a phosphoric acid compound, or a halogen-containing polyol obtained by ring-opening polymerization of epichlorohydrin or trichlorobutylene oxide. Examples thereof include polyols and phenol polyols.

Regarding the above-mentioned polyol compound, the number of hydroxyl groups of the polyol is preferably 2 to 4, the hydroxyl value is preferably 25 to 280 mgKOH / g, and 30 to 120 mgKOH / g in terms of excellent elongation elasticity and mechanical strength of the obtained cured product. More preferred.

The plasticizer is not particularly limited, and examples thereof include dioctyl phthalate (DOP), dioctyl adipate (DOA), tricresyl phosphate (TCP), and chlorinated paraffin.

The amine catalyst (tertiary amine compound) is not particularly limited, but for example, triethanolamine, bisdimethylaminoethyl ether, N, N, N', N ", N" -pentamethyldiethylenetriamine. , Hexamethyltriethylenetetramine, N, N-dimethylaminoethoxyethanol, N, N, N'-trimethylaminoethylethanolamine, and N, N-dimethylaminoethyl-N'-methylaminoethyl-N "-methylamino Isopropanol and the like can be mentioned.

The organic metal catalyst is not particularly limited, but for example, stanasdiacetate, stanasdioctate, stanasdioleate, stanasdilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, and dibutyl. Examples thereof include tin dichloride, dioctyl tin dilaurate, lead octanate, lead naphthenate, nickel naphthenate, cobalt naphthenate and the like.

The carboxylic acid metal salt catalyst is not particularly limited, and examples thereof include alkali metal salts of carboxylic acids and alkaline earth metal salts. Here, the carboxylic acid is not particularly limited, but for example, aliphatic substances such as formic acid, acetic acid, propionic acid, 2-ethylhexanoic acid and adipic acid, and fragrances such as dicarboxylic acids, benzoic acid and phthalic acid. Examples include group products and dicarboxylic acids. Further, as the metal to form the carboxylate, for example, an alkali metal such as lithium, sodium and potassium, and an alkaline earth metal such as calcium and magnesium are preferable.

The quaternary ammonium salt catalyst may be a conventionally known one and is not particularly limited, but for example, a tetraalkylammonium halide such as tetramethylammonium chloride and a tetraalkyl such as a tetramethylammonium hydroxide salt. Examples thereof include tetraalkylammonium organic acid salts such as ammonium hydroxide, tetramethylammonium 2-ethylhexanate, 2-hydroxypropyltrimethylammonium formate, and 2-hydroxypropyltrimethylammonium 2-ethylhexanoate.

The foaming agent is not particularly limited, but is, for example, 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3-pentafluorobutane (1,1,1,3,3-pentafluorobutane). HFC-365mfc), 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) and other fluorocarbon compounds, HFE- Examples thereof include hydrofluorocarbons such as 254 pc, low boiling hydrocarbons, water, liquefied carbon dioxide, dichloromethane, formic acid, acetone and the like. These may be used alone or in combination of two or more. As the low boiling point hydrocarbon, a hydrocarbon having a boiling point of usually −30 to 70 ° C. is usually used, and specific examples thereof include propane, butane, pentane, cyclopentane, hexane and mixtures thereof.

Examples of the foam stabilizer include organic silicone-based surfactants, and specifically, nonionic surfactants such as organic siloxane-polyoxyalkylene copolymers and silicone-grease copolymers, or these. A mixture of the above is exemplified.

Examples of the flame-retardant agent include tricresyl phosphate, a reactive flame-retardant agent such as a phosphorus-containing polyol such as propoxylated phosphoric acid and propoxylated dibutylpyrophosphate obtained by an addition reaction between phosphoric acid and alkylene oxide. Tertiary phosphate esters such as Tris (2-chloroethyl) phosphate, halogen-containing tertiary phosphate esters such as Tris (chloropropyl) phosphate, and halogens such as dibromopropanol, dibromoneopentyl glycol, and tetrabromobisphenol A. Examples thereof include organic compounds, antimony oxide, magnesium carbonate, calcium carbonate, inorganic compounds such as aluminum phosphate and the like.

Examples of the other additives include inorganic fillers such as calcium carbonate, talc, kaolin, zeolite, and silicon oxide, pigments such as chromium oxide, titanium oxide, red iron oxide, carbon black, and iron oxide, or hindered amines. Stabilizers such as hindered phenol type and benzothiazole type can be mentioned.

As described above, a polyurethane resin can be produced by reacting an amine-based curing agent for producing polyurethane containing at least 4,4'-methylenebis (2-bromoaniline) with an isocyanate compound.

The isocyanate compound is not particularly limited, but for example, aromatic isocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, naphthylene diisocyanate and xylylene diisocyanate, aliphatic isocyanates such as hexamethylene diisocyanate, dicyclohexyldiisocyanate, and the like. Examples thereof include alicyclic isocyanates such as isophorone diisocyanate, and mixtures thereof. The isocyanate group content in the isocyanate compound is preferably 8 to 33% by mass, more preferably 10 to 20% by mass. As these isocyanate compounds, a so-called isocyanate-terminated prepolymer obtained by partially reacting the above-mentioned polyol compound or the like can also be used. The isocyanate-terminated prepolymer is not particularly limited, but can be produced, for example, by reacting tolylene diisocyanate (TDI) with a polyol. In this case, in order to minimize the amount of TDI remaining in the free state in the obtained isocyanate-terminated prepolymer, the charged TDI and the polyol were charged so as not to exceed 2.1 in the equivalent ratio of NCO / OH. It is desirable to react.

As the polyol which is a raw material of the isocyanate-terminated prepolymer, polyether polyols, polyester polyols, polycaprolactone polyols and the like used for ordinary urethane prepolymers can be used, but the room temperature is used for the coating film waterproofing material of the present invention. A liquid, low-viscosity polyalkylene ether polyol having a molecular weight of 400 to 8000 is preferable, and the most preferable polyol is a polypropylene ether polyol or a polyethylene-propylene ether polyol, or a mixture thereof. The isocyanate content in the isocyanate-terminated prepolymer is preferably in the range of 1.5 to 8% by weight in terms of excellent elongation and mechanical strength.

As for the isocyanate compound, the above-mentioned isocyanate compound or the isocyanate group-terminated urethane prepolymer may be used alone, or both may be mixed and used. By using the isocyanate group-terminated urethane prepolymer, the elasticity and elongation of the cured coating film can be controlled.

When the present composition or the curing agent for producing a polyurethane resin containing the present composition is solid at room temperature, these are either heated and dissolved before use, or dissolved in the above-mentioned polyol compound or the above-mentioned plasticizer. It is preferable to use it.

The amine-based curing agent for polyurethane production containing 4,4'-methylenebis (2-bromoaniline) of the present invention can be used as a curing agent for a polyurethane coating waterproofing material or a coated floor material on the roof of a building, a veranda, etc. It can be preferably used for waterproofing of corridors and elastic pavement of sports facilities. For use in such applications, a two-component manual on-site mixed coating using the curing agent of the present invention (which may contain other polyol compounds as necessary) as an isocyanate reaction component (curing agent). It is preferably by the method.

The production method of the present invention relates to at least a method for producing a polyurethane resin, which comprises mixing an isocyanate compound with the above-mentioned amine-based curing agent for producing polyurethane and reacting them.

The production method of the present invention comprises a main agent containing an isocyanate compound (preferably an isocyanate-terminated prepolymer obtained by the reaction of TDI and a polyol) as a main component, and the above-mentioned amine-based curing agent for polyurethane production (optionally, a polyol compound). (Including catalyst, etc.) is mixed at the construction site and applied onto the object to be coated, and the isocyanate group of the main agent and the amino group of the aromatic polyamine of the curing agent (in the case of containing a polyol compound, the amino group and the hydroxy group) are mixed. It can be carried out by reacting with (total) and curing. At this time, the equivalent ratio (NCO / (NH ₂ + OH)) of the isocyanate group of the main agent to the amino group of the aromatic polyamine of the curing agent is 1.0 / 1.3 in terms of the curability and mechanical properties of the coating film. It is preferable to mix so as to be ~ 1.0 / 0.5, and more preferably 1.0 / 1.0 to 1.0 / 0.8.

According to the method of the present invention, stable construction can be performed throughout the year, and a cured coating film suitable for applications such as a waterproof coating film having excellent heat resistance and a coating flooring material having good finish without stickiness in a short time. Is obtained. The manufacturing method of the present invention is preferably carried out by manual mixing, but since the pot life and levelable time can be long, it is also possible to construct a machine using an automatic mixing device such as a static mixer or a dynamic mixer. Can be used.

The time course of the hardness (amplitude value of the scanning vibration needle type curing tester) of the urethane resin composition during the curing reaction is shown in a graph.

Hereinafter, the present invention will be specifically described with reference to Examples. However, these do not limit the present invention.
[NMR analysis]
Measuring device: JNM-ECZ400S manufactured by JEOL Ltd.
[GC analysis]
Measuring device: Shimadzu Nexus GC-2030
[Evaluation of pot life and curing characteristics]
Measuring device: Smithers RAPRA technology RAPRA SVNC (scanning type vibrating needle type curing tester)
Synthesis Example 1 (Synthesis of 4,4'-methylenebis (2-bromoaniline))
82.0 g (0.414 mmol) of 4,4'-methylenebis (aniline) (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2 L of acetic acid were added to a 3 L separable flask under a nitrogen stream, and the mixture was stirred at room temperature until completely dissolved. To this, 101 g (0.989 mmol) of acetic anhydride was added dropwise over 20 minutes, and the mixture was stirred at room temperature for 2 hours to obtain a white pink slurry. Next, a solution of 132 g (0.828 mmol) of bromine diluted with 350 mL of acetic acid was added dropwise to the obtained white-pink slurry over 1 hour at room temperature, and the mixture was stirred at the same temperature for 17 hours. An aqueous sodium nitrite solution was added to the obtained red solution to remove unreacted bromine, and then the reaction solution was added to 4 L of water to precipitate a solid. This solid was filtered, washed with water, and then dried to obtain 150 g of a white solid.

150 g of the obtained white solid was placed in a 5 L separable flask, 4 L of 1,4-dioxane, 500 mL of methanol and 76.0 g (0.828 mmol) of sodium hydroxide were added, and the mixture was stirred under heating reflux conditions (82 ° C.) for 5 hours. .. After allowing to cool to room temperature, the insoluble component was filtered, and the obtained filtrate was concentrated to obtain a light orange solid. By recrystallizing this solid with methanol and water, 75.1 g (yield 52%, GC purity 99.5%) of a light beige solid (4,5'-methylenebis (2-bromoaniline)) was obtained. .. Compound identification was performed by ¹ H-NMR and melting point measurement.

^{1 1} H-NMR (CDCl ₃ ) δ (ppm) = 3.71 (s, 2H), 3.98 (s, 4H), 6.68 to 6.70 (d, 2H), 6.88 to 6. 91 (d, 2H), 7.20 (s, 2H)
Melting point = 115 ° C.

Example 1 (evaluation of pot life and curing characteristics)
4.2'-methylenebis (2-bromoaniline) (amine value = 5.6 mmol / g) 7.2 g (synthesis example 1) preheated to 120 ° C. and TDI prepolymer (product name) preheated to 120 ° C. Coronate 4089, NCO content = 4.20%, manufactured by Tosoh Corporation, hereinafter referred to as C-4089) 42.8 g was mixed at 120 ° C. for 1 minute (mixed molar ratio of NCO / NH ₂ was 1.00 / 0). .94), vacuum degassed for about 15 seconds. Then, it was immediately placed on a measurement plate of RAPRA SVNC, and the curing behavior was measured at 120 ° C. As a result, the time when the numerical value of the amplitude became 8000 (a guideline for pot life) was 7 minutes and 1 second, and the time when the numerical value of the amplitude became 1000 or less (a guideline for curing) was 8 minutes and 39 seconds. The change in the amplitude value with the elapsed time is shown in FIG.

Comparative Example 1 (Evaluation of pot life and curing characteristics)
5.6 g of MOCA (amine value = 7.5 mmol / g Fuji Film Wako Pure Chemical Industries, Ltd. first grade) preheated at 80 ° C. and 44.4 g of C-4089 preheated at 80 ° C. were mixed at 80 ° C. for 1 minute ( The mixed molar ratio of NCO / NH ₂ was 1.00 / 0.95), and vacuum degassed for about 15 seconds. Then, it was immediately placed on a measurement plate of RAPRA SVNC, and the curing behavior was measured at 120 ° C. As a result, the time when the numerical value of the amplitude became 8000 (a guideline for pot life) was 5 minutes and 38 seconds, and the time when the numerical value of the amplitude became 1000 or less (a guideline for curing) was 11 minutes and 44 seconds. The change in the amplitude value with the elapsed time is shown in FIG.

As shown in FIG. 1, when 4,4'-methylenebis (2-bromoaniline) is used as a curing agent, it has a longer pot life and higher curing characteristics (compared to the case where MOCA is used as a curing agent). It was found to have curing).

Example 2 (Preparation of polyurethane elastomer using 4,4'-methylenebis (2-bromoaniline) and measurement of physical properties)
171 g of coronate preheated to 120 ° C. and 29 g of 4,4'-methylenebis (2-bromoaniline) (amine value = 5.6 mmol / g) preheated to 120 ° C. were mixed (mixture of NCO / NH ₂ ). A thermosetting polyurethane elastomer-forming composition having a molar ratio of 1.00 / 0.95) was prepared. Immediately, this composition was poured into a mold for forming a 2 mm thick flat plate sheet preheated to 120 ° C., allowed to stand at a temperature of 120 ° C. for 5 hours to be cured, and then the obtained cured product was obtained. I took it out of the mold. Then, it was cured in a constant temperature room at 25 ° C. for one week to obtain a polyurethane elastomer molded product. The following items were measured for the obtained polyurethane elastomer molded product. The measurement results are shown in Table 1.
(1) JIS-A hardness (hardness): Measured using an A-type hardness tester according to JIS K7312.
(2) Tensile strength ( _TB ), modulus (M ₁₀₀ ), elongation ( _EB ): Measured according to JIS K7312.
(3) Compression set (CS): Measure 25% compression value according to JIS K6262.
(4) Glass transition temperature (Tg): Measurement was carried out under the following conditions using a viscoelasticity measuring device DMA7100 (manufactured by Hitachi High-Tech Science). The temperature showing the maximum value of tan δ (tangent loss) was defined as the glass transition temperature.
Sample shape: 20 mm x 5 mm x 2 mm
Measurement temperature range, temperature rise rate: -50 ° C to 150 ° C, 2 ° C / min
Measurement mode: Tension measurement frequency: 10Hz
Comparative Example 2 (Making MOCA Elastomer and Measuring Physical Properties)
The amount of C-4089 used is 177.5 g, and 22.5 g of MOCA (amine value = 7.5 mmol / g Fuji Film Wako Pure Chemical Industries, Ltd.) is used instead of 4,4'-methylenebis (2-bromoaniline). The same operation as in Example 2 was carried out to obtain a MOCA polyurethane elastomer molded product (mixed molar ratio of NCO / NH ₂ was 1.00 / 0.95). The same measurement as in Example 2 was carried out on the obtained polyurethane elastomer molded product. The measurement results are shown in Table 1.

As shown in Table 1, the polyurethane elastomer molded product using 4,4'-methylenebis (2-bromoaniline) as a curing agent showed the same mechanical properties as the conventional MOCA polyurethane elastomer molded product.

According to the present invention, it is possible to provide an amine-based curing agent having a higher reactivity than MOCA. In particular, since it has both a long pot life and high curing characteristics (curing), it can be preferably used at various polyurethane construction sites.

Claims (3)

An amine-based curing agent for producing polyurethane, which comprises 4,4'-methylenebis (2-bromoaniline). In addition to the above 4,4'-methylenebis (2-bromoaniline), diethyltoluenediamine, 2,2', 3,3'-tetrachloro-4,4'-diaminodiphenylmethane, 3,3'-diethyl. -5,5'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dichloro-3,3', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 2,2'-dichloro- 5,5'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylmethane, 4,4'-methylenebis (N-sec-butylaniline), 4,4 '-Methylenebis (N-methylaniline), 1,2-bis (2-aminophenylthio) ethane, 2-ethyl-4,6-dimethyl-1,3-benzenediamine, 4-methyl-2,6-bis It is characterized by containing a compound selected from (methylthio) -1,3-benzenediamine, 3,5-diamino-4-chloro-methylpropyl benzoate, 2,4-diaminotoluene, and 2,6-diaminotoluene. The amine-based curing agent for producing polyurethane according to claim 1. A method for producing a polyurethane resin, which comprises mixing and reacting at least an isocyanate compound with the amine-based curing agent for producing polyurethane according to claim 1 or 2.

Images