JP6565229B2 - Curing agent for epoxy resin - Google Patents

Description

  The present invention relates to a modified aliphatic amine for an epoxy resin curing agent. Furthermore, the present invention relates to an epoxy resin curing agent containing the modified aliphatic amine, an epoxy resin composition containing the epoxy resin curing agent, and an epoxy resin cured product obtained by curing the epoxy resin composition.

  The epoxy resin composition comprises an epoxy resin, an epoxy resin curing agent, various additives, and the like, and is used in various applications such as civil engineering, building materials, and daily necessities. As the epoxy resin curing agent, polyfunctional polyamines are generally used, and examples thereof include aliphatic amines, aromatic amines, and polyether amines.

  Among these polyamines, for example, polyethylene polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine are used as the aliphatic amine. However, although these polyamines have low viscosity, they are highly toxic and have strong skin irritation. In addition, when used as an epoxy resin curing agent, the epoxy resin composition absorbs carbon dioxide and water vapor in the atmosphere to absorb carbamine. Since it is easy to produce acid salts and carbonates, it has defects such as whitening phenomenon and adhesion phenomenon of the coating film and deterioration of the coating film appearance.

  Therefore, these polyamines are attributed to the reactivity of the amino group of each polyamine, that is, active hydrogen, depending on the purpose of improving safety and health, improving workability, and imparting cured product performance suitable for the application. In most cases, it is used after being modified to suit the characteristics. Typical modification methods for polyamines include (1) modification by Mannich reaction between a phenolic compound and an aldehyde compound, (2) modification by reaction with an epoxy compound, and (3) modification by reaction with a compound having a carboxyl group. (4) Modification by Michael addition reaction with an acrylic compound, and (5) Modification by a combination thereof. However, even if these modification methods are used, there has not been proposed a modified polyamine satisfying all of the viscosity reduction, long pot life, and normal temperature curing time of the epoxy resin composition.

  Furthermore, a coating material comprising an epoxy resin composition in which the epoxy resin curing agent contains a modified chain aliphatic polyamine obtained by addition reaction of diethylenetriamine or triethylenetetramine and styrene has been proposed (for example, Patent Document 1). However, even if these amines are used, the effect of reducing the viscosity is insufficient and the room temperature curability is excellent, but there is a problem that the pot life is short.

Japanese Patent No. 4321101

  The present invention has been made in view of the above-described background art, and its purpose is to reduce the initial viscosity of a system in which an epoxy resin and an epoxy resin curing agent are mixed, extend the pot life, and improve the room temperature curability. is there.

  As a result of intensive studies on the amine for epoxy resin curing agents, the present inventors have found a novel modified aliphatic amine for epoxy resin curing agent that can solve the above problems, and have completed the present invention.

  That is, this invention relates to the hardening | curing agent for epoxy resins as shown below, and the epoxy resin hardened | cured material obtained using it.

[1]
The hardening | curing agent for epoxy resins containing 1 type, or 2 or more types of amine compounds shown by the following general formula (1) or (2).

[In General Formula (1), R _{1 to} R ₄ each independently represent a hydrogen atom, a phenyl group, or a substituent represented by the following General Formula (3), and at least one of R _{1 to} R ₄ One is a substituent other than a hydrogen atom. m represents an integer of 2 to 6.

In General Formula (2), R _{5 to} R ₈ each independently represent a hydrogen atom, a phenyl group, or a substituent represented by the following General Formula (3), and at least one of R _{5 to} R ₈ Is a substituent other than a hydrogen atom. m represents an integer of 1 to 2;

n represents an integer of 0 to 3. When n is 0, R ₉ represents a hydrogen atom, and when n is 1 to 3, R ₉ represents any one of a hydrogen atom, a methyl group, and an ethyl group. R _{10 to} R ₁₁ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a methoxy group, an ethoxy group, or a hydroxyl group. R _{10 to} R ₁₁ may be bonded to each other to form a saturated or unsaturated condensed ring. ]
[2]
The amine compound represented by the general formula (1) is phenylethylethylenediamine, phenylethylpropanediamine, phenylethylbutanediamine, phenylethylpentanediamine, phenylethylhexamethylenediamine, phenylpropylethylenediamine, phenylpropylpropanediamine, phenylpropylbutanediamine. The curing agent for epoxy resins according to [1] above, which is at least one selected from the group consisting of phenylpropylpentanediamine and phenylpropylhexamethylenediamine.

[3]
The amine compound represented by the general formula (2) is phenylethyl 3-oxapentane-1,5-diamine, phenylethyl 3,6-dioxa-1,8-octanediamine, phenylpropyl 3-oxapentane-1, The curing agent for epoxy resins according to [1] above, which is at least one selected from the group consisting of 5-diamine and phenylpropyl 3,6-dioxa-1,8-octanediamine.

[4]
The curing agent for epoxy resins according to any one of the above [1] to [3], further comprising an amine compound obtained by a reaction between an aliphatic amine and an aromatic halogen compound.

[5]
The curing agent for epoxy resin according to any one of the above [1] to [3], further comprising an amine compound obtained by a reaction between an aliphatic amine and an alkenyl compound.

[6]
An epoxy resin composition comprising the epoxy resin curing agent according to any one of [1] to [5] and an epoxy resin.

[7]
A cured epoxy resin obtained by curing the epoxy resin composition according to the above [6].

[8]
A method for producing a cured epoxy resin product, comprising curing the epoxy resin composition according to the above [6].

  The curing agent for epoxy resin according to the present invention has a reduced initial viscosity when reacted with an epoxy resin rather than a modified chain aliphatic polyamine obtained by addition reaction of conventional diethylenetriamine or triethylenetetramine with styrene, Since it is excellent in the effect of extending and improving the room temperature curability, it is extremely useful industrially.

  Hereinafter, the present invention will be described in detail.

  The hardening | curing agent for epoxy resins of this invention is characterized by including the 1 type (s) or 2 or more types of the amine compound shown by the said General formula (1) and (2).

The curing agent for epoxy resin of the present invention includes, for example, an aliphatic amine and an aromatic compound in which R _{1 to} R ₈ in the general formulas (1) and (2) are all hydrogen atoms (that is, unmodified). Can be easily obtained by reacting.

The aliphatic amine used as a raw material in these reactions, in which R _{1 to} R ₄ in the general formula (1) are all hydrogen atoms, is not particularly limited. For example, ethylenediamine, propanediamine, butanediamine, Examples include pentanediamine and hexamethylenediamine.

Moreover, although it does not specifically limit as aliphatic amine whose R < ₅ > -R < ₈ > in the said General formula (2) used as a raw material by these reaction is a hydrogen atom, For example, 3-oxapentane-1 , 5-diamine, 3,6-dioxa-1,8-octanediamine.

  The aromatic compound used as a raw material in this reaction can be any aromatic compound and is not particularly limited. For example, styrene, allylbenzene, α-methylstyrene, 2-bromoethylbenzene, 4-methyl Styrene, 4-methoxystyrene, 1-allyl-4-methylbenzene, 4-vinylphenol, 4-allylphenol, 1-vinylnaphthalene, 4-vinyl-1-naphthol, (3-bromopropyl) benzene, phenylacetaldehyde, And benzyl cyanide.

  Among these raw materials, when an alkenyl compound such as styrene, allylbenzene, and α-methylstyrene is reacted with an aliphatic amine, it is preferable to use a catalyst exhibiting strong basicity. For example, there are alkali metals, alkali metal amides, alkylated alkali metals and the like, and lithium hydride and lithium amide are particularly preferable. The amount of the catalyst used varies depending on the type of raw material, reaction ratio, reaction temperature, and the like, but is usually 0.05 to 5% by weight, preferably 0.1 to 3% by weight in the raw material.

  Among these raw materials, when a halogen compound such as 2-bromoethylbenzene or (3-bromopropyl) benzene and an aliphatic amine are reacted, it is not essential to use a catalyst. Hydrogen halides by-produced by the reaction, such as hydrogen bromide and hydrogen chloride, may be separated after treatment with a strong base such as sodium hydroxide.

Among these raw materials, when phenylacetaldehyde, benzyl cyanide and the like are reacted with an aliphatic amine, it is preferably carried out in the presence of a hydrogenation catalyst. Examples of the hydrogenation catalyst include commonly used hydrogenation catalysts such as nickel, Raney nickel, Raney cobalt platinum black, platinum oxide, palladium, palladium / activated carbon (Pd / C), and the like. The amount of the catalyst used is preferably in the range of 0.1 to 10% by weight based on the aliphatic amine in which R _{1 to} R ₈ in the general formulas (1) and (2) are all hydrogen atoms. Moreover, it is preferable to implement this reaction on 90-150 degreeC temperature conditions. When the reaction is carried out at a low temperature below 90 ° C., problems such as remaining unreacted aliphatic amine and an increase in the amount of by-products generated may occur.

  Moreover, you may make the amine for epoxy resin hardening | curing agents of this invention contain other polyfunctional amine in the range which does not deviate from the summary of this invention. Examples of such polyfunctional amines include, but are not limited to, piperazine, meta-xylylenediamine, isophoronediamine, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4 ′. -Diaminodicyclohexylmethane, 2,4'-diaminodicyclohexylmethane, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, bis -(3-aminopropyl) amine, N, N'-bis- (3-aminopropyl) -1,2-diaminoethane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, Polyoxyalkylene polyamines (for example, Jeffamine D-230) Jeffamine D-400, Jeffamine D-2000, Jeffamine D-4000, Jeffamine T-403, etc.) and the like.

  Further, the polyamidoamine-modified product, amidoamine-modified product, Mannich-modified product, amine-epoxy adduct-modified product, and Michael addition-modified product in the amine composition for an epoxy resin curing agent of the present invention are preferably used as an epoxy resin curing agent. You can also These modified products can be prepared by a conventionally known method.

  Next, the epoxy resin composition of the present invention will be described.

  The epoxy resin composition of the present invention includes the above-described curing agent for epoxy resin of the present invention and an epoxy resin.

  Although it does not specifically limit as an epoxy resin, For example, the uncured polyepoxy compound containing 2 or more 1, 2- epoxy groups per molecule is mentioned. Specifically, polyfunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, epoxy novolac resin, alicyclic epoxy resin, polyfunctional epoxy resin, and brominated epoxy resin are exemplified. These epoxy resins can be used either without solvent or diluted with a solvent.

  The epoxy resin curing agent and epoxy resin of the present invention contained in the epoxy resin composition of the present invention are [total number of moles of amine hydrogen atoms in the curing agent for epoxy resin of the present invention] / [in epoxy resin] The total number of moles of epoxy groups] (molar ratio) is usually in the range of 1.5 / 1 to 1 / 1.5, preferably in the range of 1.2 / 1 to 1 / 1.2. By doing in this way, the cured | curing material property of a favorable epoxy resin can be exhibited. In the present invention, “amine hydrogen atom” refers to a hydrogen atom bonded to a nitrogen atom in an amino group.

  In addition to the curing agent for epoxy resins of the present invention, a conventionally known curing accelerator can be used in combination with the epoxy resin composition of the present invention. Such a curing accelerator is not particularly limited, and examples thereof include organic acid compounds, alcohol compounds, phenols, tertiary amines, hydroxylamines, and similar compounds. Among these, particularly useful curing accelerators include, for example, phenol, nonylphenol, cresol, bisphenol A, salicylic acid, dimethylaminomethylphenol, bis (dimethylaminomethyl) phenol, tris (dimethylaminomethyl) phenol, and the like. It is done.

  Moreover, a conventionally well-known plasticizer can be used for the epoxy resin composition of this invention. Such a plasticizer is not particularly limited, and examples thereof include benzyl alcohol, nonylphenol, various phthalates, and the like.

  Furthermore, you may use a solvent, a filler, a pigment, a pigment dispersant, a rheology modifier, a thixotropic agent, a fluidization and smoothing adjuvant, an antifoaming agent, etc. for the epoxy resin composition of this invention. Suitable solvents include, for example, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, esters, ketones, ethers, alcohols and the like.

  Next, the cured epoxy resin of the present invention will be described.

  The cured epoxy resin of the present invention can be obtained by reacting the epoxy resin curing agent of the present invention with the epoxy resin in the epoxy resin composition of the present invention. The reaction between the epoxy resin curing agent and the epoxy resin of the present invention is not particularly limited. For example, a cured product is formed by mixing and contacting these. If necessary, heat treatment can be performed to forcibly cure.

  The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited thereto.

[Production Example 1] (Preparation of amine for epoxy resin curing agent)
In a 1 liter flask equipped with a stirrer, thermometer, nitrogen introduction tube, dropping funnel, and cooling tube, 60.1 g (1.0 mol) of ethylenediamine (manufactured by Tosoh Corporation) and lithium hydride (manufactured by Sigma-Aldrich Japan GK) ) 0.2 g (0.02 mol; 0.3 wt%) was charged, and the temperature was raised to 80 ° C. with stirring in a nitrogen stream. While maintaining the temperature at 80 ° C., 10.4 g (0.1 mol) of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped over 2 hours. After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, then cooled to room temperature, added with 3.6 g (0.2 mol) of water and stirred. After the precipitate in the liquid in the flask was separated by filtration, unreacted excess amine was distilled off using reduced pressure distillation. Then, it refine | purified using vacuum distillation and obtained 6.6 g (0.04 mol) of phenyl ethyl ethylenediamine which is a target object.

[Production Example 2] (Preparation of amine for epoxy resin curing agent)
The target product, phenylethylhexamethylenediamine, was reacted and distilled in the same manner as in Production Example 1 except that 116.2 g (1.0 mol) of hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was charged instead of ethylenediamine. 8.8 g (0.04 mol) was obtained.

[Production Example 3] (Preparation of amine for epoxy resin curing agent)
Into a 2 liter flask equipped with a stirrer, thermometer, nitrogen introduction tube, dropping funnel, and cooling tube was charged 116.2 g (1.0 mol) of hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) under a nitrogen stream, The temperature was raised to 80 ° C. with stirring. While maintaining at 80 ° C., 18.5 g (0.1 mol) of 2-bromoethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 5 hours. After completion of the dropwise addition, the mixture was kept at 80 ° C. for 1 hour, cooled to room temperature, and 16.7 g (0.2 mol) of 48% sodium hydroxide was added and stirred. After the precipitate in the liquid in the flask was separated by filtration, unreacted excess amine was distilled off using reduced pressure distillation. Then, it refine | purified using vacuum distillation and obtained 11.0 g (0.05 mol) of phenylethyl hexamethylenediamine which is a target object.

[Production Example 4] (Preparation of amine for epoxy resin curing agent)
The reaction and distillation were carried out in the same manner as in Production Example 1, except that 148.2 g (1.0 mol) of 3,6-dioxa-1,8-octanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of ethylenediamine, As a result, 7.6 g (0.03 mol) of phenylethyl 3,6-dioxa-1,8-octanediamine was obtained.

[Production Example 5] (Preparation of amine for epoxy resin curing agent)
The reaction and distillation were conducted in the same manner as in Production Example 2 except that 11.8 g (0.1 mol) of allylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of styrene, and phenylpropylhexamethylenediamine 9 which was the target product was obtained. 0.4 g (0.04 mol) was obtained.

[Production Example 6] (Preparation of amine for epoxy resin curing agent)
The reaction and distillation were carried out in the same manner as in Production Example 1 except that 103.2 g (1.0 mol) of diethylenetriamine (manufactured by Tosoh Corporation) was used instead of ethylenediamine, and 6.2 g (0. 03 mol) was obtained.

<Evaluation of initial viscosity and pot life>
10 g of an epoxy resin composition obtained by mixing an epoxy resin and an epoxy resin curing agent is cured under a constant condition of 23 ° C., and using a vibration viscometer (trade name: VM-10A, manufactured by Seconic Corporation). The change in viscosity over time was measured. The measured value of the epoxy resin composition immediately after mixing the epoxy resin and the epoxy resin curing agent for 1 minute was defined as the initial viscosity. The lower the initial viscosity, the easier it is to apply the epoxy resin composition while maintaining good smoothness.

  The time until the viscosity value of the epoxy resin composition increased and reached twice the initial viscosity value with the passage of time after mixing the epoxy resin and the epoxy resin curing agent was defined as the pot life. The longer the pot life is, the longer the epoxy resin composition after mixing can be used.

<Evaluation of room temperature curability>
Uniformly apply an epoxy resin composition obtained by mixing an epoxy resin and an epoxy resin curing agent onto a glass plate (350 × 25 × 1.3 [mm]) using an applicator adjusted to a film thickness of 76.2 μm. Then, it was cured for 48 hours under constant conditions of 23 ° C. and 50% relative humidity using a paint drying time measuring device type II (manufactured by Dazai Equipment Co., Ltd.). The time at which the linear marks due to the needle attached to the paint drying time measuring device completely disappeared was defined as the room temperature curing time.

The shorter the room temperature curing time, the better the work efficiency and the higher the productivity.
<Evaluation of coating state>
The state of the cured epoxy resin after 72 hours from the mixing of the epoxy resin and the epoxy resin curing agent was visually confirmed, and the state of transparency or whitening was judged. Furthermore, the adhesiveness of the coating film was evaluated stepwise by touch, and expressed as a dry touch. A transparent and tack-free coating is preferred.

Example 1
Epoxy obtained by adding 3.0 g of phenylethylethylenediamine obtained in Production Example 1 to 10.0 g of epoxy resin (jER828, manufactured by Mitsubishi Chemical Corporation) and stirring at room temperature for 1 minute using a spatula Table 1 shows the results of curing the resin composition according to the above evaluation method and measuring the curing performance of the coating film.

  In Table 1, [total number of moles of amine hydrogen atoms in curing agent for epoxy resin] / [total number of moles of epoxy group in epoxy resin] (molar ratio) is 1. Adjustment was made to be 05 / 1.00.

Examples 2 to 7 and Comparative Examples 1 to 9
The curing performance of the coating film was measured in the same manner as in Example 1 except that the types and amounts of amines shown in Table 1 were used. The results are also shown in Table 1.

As is clear from Examples 1 to 7, the epoxy resin composition prepared using the curing agent for epoxy resin of the present invention has a low initial viscosity, a long pot life, and a short normal temperature curing time. On the other hand, the epoxy resin compositions obtained in Comparative Examples 1 to 9 had curing performance inferior to that of the Examples in at least one item. Furthermore, the epoxy resin coating film cured in Examples 1 to 7 was excellent in transparency and drying property as compared with the coating films obtained in Comparative Examples 1 to 9.

  The epoxy resin curing agent of the present invention is an amine composition that provides an epoxy resin composition having a low viscosity and a long pot life, and has a possibility of being widely used in the production field of epoxy resin curing agents.

Claims (7)

The hardening | curing agent for epoxy resins containing the 1 type (s ) or 2 or more types of amine compounds shown by the following general formula (1 ) .
[In General Formula (1), R _{1 to} R ₄ each independently represent a hydrogen atom, a phenyl group, or a substituent represented by the following General Formula (3), and at least one of R _{1 to} R ₄ One is a substituent other than a hydrogen atom. m represents 6 .
n represents an integer of 0 to 3. When n is 0, R ₉ represents a hydrogen atom, and when n is 1 to 3, R ₉ represents any one of a hydrogen atom, a methyl group, and an ethyl group. R _{10 to} R ₁₁ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a methoxy group, an ethoxy group, or a hydroxyl group. R _{10 to} R ₁₁ may be bonded to each other to form a saturated or unsaturated condensed ring. ] Amine compound represented by the general formula (1) is full E sulfonyl ethyl hexamethylenediamine, and phenylpropyl epoxy resin according to claim 1, characterized in that hexamethylene least one diamine selected from the group consisting of Curing agent. The curing agent for an epoxy resin according to claim 1 or 2 , further comprising an amine compound obtained by a reaction between an aliphatic amine and an aromatic halogen compound. The curing agent for epoxy resins according to claim 1 or 2 , further comprising an amine compound obtained by a reaction between an aliphatic amine and an alkenyl compound. It claims 1 to epoxy resin composition which comprises an epoxy resin curing agent according to any one of claims 4 and the epoxy resin. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 5. A method for producing a cured epoxy resin product comprising curing the epoxy resin composition according to claim 5.