JPS6017210B2 - Hardener for epoxy resin - Google Patents

Description

[Detailed description of the invention] The present invention relates to a curing agent for epoxy resin.

The object of the present invention is to provide an epoxy resin that has good compatibility with epoxy resins, exhibits excellent storage stability, has a sufficiently long shelf life around room temperature, and can be cured quickly even at relatively low temperatures when heated. The object of the present invention is to provide a curing agent that provides a resin composition.

Epoxy resin can be cured mechanically, thermally,
Because it becomes a cured product with excellent electrical and various properties, it is widely used in various molding materials, composite materials, paints, adhesives, etc.

Conventionally, acid anhydrides, boron trifluoride amine complexes, or amine compounds have been generally used as curing agents for epoxy resins. Although curing agents with a high It has the disadvantage that it tends to become inactivated and affect the performance of the cured product.

On the other hand, in the case of a curing agent that has a relatively fast curing speed, such as an amine compound, it is economically advantageous not only because it shortens the curing time required for molding, but also because it reduces the curing temperature, thereby reducing energy costs and auxiliary material costs. Yes, it is very meaningful in practical terms. However, on the other hand, it has had the problem that it lacks work stability because its moldability time at around room temperature, which is necessary as a molding material, is extremely short, and its moldability changes in a short period of time. Furthermore, amine compounds generally have toxicity problems and lack generality. In order to solve these drawbacks, the present inventors have developed an epoxy resin composition that exhibits sufficient storage stability and work stability near room temperature, and has excellent compatibility to provide an epoxy resin composition that can be rapidly cured even at relatively low temperatures when heated. The present invention was completed as a result of research into latent curing agent compositions.

That is, the present invention relates to a curing agent composition for epoxy resin, which comprises one or more imidazole compounds and one or more aromatic urea compounds represented by the following general formula (X and Y=-C , 1Br, 1C ratio, 1N02, 1 day, 10C 2 days 5 or -OCH3R
, and R2=alkyl group, allyl group, alkoxy group,
It represents an alkenyl group, an aralkyl group, or an alicyclic compound containing both R and R2.

) and 0.5 to 6.0% of the imidazole compound in this curing agent. The curing agent for epoxy resin contains one or more aromatic monobasic acids or aromatic dibasic acids in a diprotic molar ratio.

If the imidazole compound used in the present invention is used alone, it has poor storage stability and short shelf life, which limits practical use.On the other hand, when aromatic urea is used alone, the curing speed is still insufficient. Curing requires high temperatures and a long time, and the resulting epoxy resin has the disadvantage of being extremely brittle.

However, if the cured composition of the present invention is used, 8
It has now become possible to provide an epoxy resin that cures rapidly in a short period of time even at relatively low temperatures of 0 to 140 qo, and has a sufficient working time and work stability near room temperature. By adding aromatic monobasic acid or aromatic dibasic acid in an amount of 0.5 to 6.0 times the mole of the compound, it is possible to easily cure the epoxy resin composition at room temperature without reducing the curability of the epoxy resin composition containing these curing agents. The time can be extended. The epoxy resin to which the curing agent of the present invention is applied refers to all known epoxy resins, such as diphenylol alkanes such as diphenylole-propane, diphenylolethane, and diphenylole-methane. Polyglycidyl ethers of /borac or polyhydric phenols such as resol, produced by epoxidation of alicyclic compounds such as cyclohexene, cyclobentadiene, dicyclobentadiene, etc. Epoxy resins, such as (3,4-epoxy-6-methyl-cyclohexyl) methyl esters of 3,4-epoxy-6-methyl-cyclohexane-carboxylic acids, or poly(epoxyalkyl) ethers of aliphatic polyoxy compounds such as ethylene glycol and glycerin, or Refers to epoxyalkyl esters of carboxylic acids such as glycidyl esters of aromatic and aliphatic carboxylic acids.
Also, USP3390037, USP297098 included
It may be a precondensate of an epoxy resin and a curing agent as described in P3067170, or it may be a simple mixture. These may be used singly or in combination of two or more.

The imidazole compound used in the present invention is not particularly limited, but examples include 2-methyl-imidazole, 2-methyl-imidazole, and 2-methyl-imidazole.
1-ethylimidazole, 2-isopropylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 2-phenylimidazole, 1-
Penzyl-2-methyl-imidazole, 1-cyanoethyl-2-methyl-imidazole, 1-cyanoethyl-2
-isopropyl-imidazole, 1-cyanoethyl-2
-Ethyl-4-methyl-imidazole, 1-cyanoethyl-2-undecyl-imidazole, 1-cyanoethyl-2-phenylimidazole, 2-ethyl-4-methyl-imidazole, 2-ethyl-4-phenylimidazole, 2-cyclohexyl- 4-methyl-imidazole, 2-butoxy-4-aryl-imidazole, 2-carpoethoxy-4-methyl-imidazole, 2-octyl-4-hexy-imidazole, 2-phenyl-4-
Methyl-imidazole, 4-butyl-5-ethyl-imidazole, 2-methyl-5-ethyl-imidazole, 2
．． Specific examples include imidazoles such as 5-dichloro-4-ethylimidazole, and imidazoles such as penzimidazole and 2-phenylbenzimidazole.

When using the curing agent of the present invention, the amount of imidazole compound to be used is desirably 0.1% to 3% by weight, more preferably 0.5% to 1% by weight based on the epoxy resin.
It is 5% by weight.

The aromatic urea compound used in the present invention is not particularly limited, but is a compound represented by the following general formula, (x and Y=-C, 1Br, 1CH3, 1N02, 10C2day5 or OCH3R, and R2 = alkyl group, allyl group, alkoxy group, alkenyl group, or aralkyl group, or an alicyclic compound containing R and R2 at the same time) For example, N-(3-chloro4- methoxyphenyl)-N',N'-dimethylurea, N-(4-chloro.

phenyl)-N',N'-dimethyl urea, N-(3
-chloro-4-ethylphenyl)-N',N'-dimethyl urea, N-(4-chlorophenyl)-N',N'
-dipropyl urea, N-(3-chloro4-methylphenyl)-N',N'-dimethyl urea, N-(3
．． 4-dichlorophenyl)-N', N'-dimethyl urea, N-(4-methyl-3-nitrophenyl)-N'
, N'-dimethyl urea, N-(3-chloro-4-methylphenyl)-N',N'-dimethyl urea, N-(3-chloro-4-ethyl-phenyl)-N',N'-dimethyl urea, N-(3-chloro-4-methoxyphenyl)-N',N'-dimethyl urea, N-(4
-ethoxyphenyl)-N',N'-dimethyl urea, N-(4-methyl-3-nitrophenyl)-N',N
Specific examples include N-dimethyl urea, N-(4-chlorophenylcarbamoyl)piveridine, N-(4-chlorophenyl-carbamoyl) morpholine, N-(4-chlorophenyl-carbamoyl)pyrrolidine, etc. When using the curing agent of the present invention, the amount of the aromatic urea compound used is preferably 0.1% to 30% by weight, and more preferably 0.5 to 15% by weight based on the epoxy resin. Examples of the aromatic monobasic acid or aromatic dibasic acid used in the present invention include benzoic acid, o, m, p-methylbenzoic acid, o, m, p-ethylbenzoic acid, dimethylbenzoic acid, and tri-methylbenzoic acid. Aromatic monocarboxylic acids and derivatives thereof such as acids, o
, m, p-benzene dicarboxylic acid, aromatic dicarboxylic acids such as methyl isophthalic acid, and derivatives thereof;
Monohydric phenols such as phenol, o, m, p-cresol, o, m, p-ethyl phenol, dimethylphenol, chlorophenol, dichlorophenol and their derivatives, biphenyls such as diphenol and derivatives thereof, compounds such as bisphenol A and derivatives thereof, dihydric phenols such as o, m, p-dihydroxybenzene, homocatechol, cresorcinol, orcinol, hydrotorquinone, 8-orcinol, and derivatives thereof, benzene sulfonic acid,
Monofunctional or difunctional aromatic sulfonic acids such as toluene sulfonic acid, xylene sulfonic acid, benzene di-sulfonic acid, chlorobenzene sulfonic acid, and derivatives thereof, hydroxybenzoic acid, hydroxy methyl benzoic acid, Refers to aromatic hydroxy carboxylic acids and their derivatives such as chlorohydroxybenzoic acid and dichlorohydroxybenzoic acid, aromatic hydroxy sulfonic acids such as phenol sulfonic acid and their derivatives, and these aromatic mono- or dibasic acids. is 0.5 to 6.0 times the mole of the imidazole compound, more preferably 1
．． 0 to 5.0 moles of one kind or two or more kinds are mixed.

The curing agent composition used in the present invention is a mixture of the imidazole compound and the aromatic urea compound, and a mixture of an aromatic monobasic acid or an aromatic dibasic acid to the above composition. It is obtained by maintaining the temperature at 100d0 and mixing uniformly.

In this case, if necessary, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, or solvents such as dioxane, dimethylacetamide and dimethylformamide may be used to dissolve and mix. The curing agent composition of the present invention has extremely good solubility in solvents or epoxy resins, and the epoxy resin containing the curing agent has a uniform composition and cures with excellent mechanical strength and heat distortion temperature. give something. The present invention will be explained in detail below with reference to Examples. Example 1 1-cyanoethyl-2-methyl-imidazole as an imidazole compound4. Take the mountain pass and add N-(3-chloro-4-methylphenyl) as an aromatic urea compound.
-N',N'-dipropylurea (5 parts) was added and mixed uniformly to obtain a curing agent.

To the curing agent composition, 10 parts of a bisphenol type epoxy resin with an epoxy equivalent of 475 was added as an epoxy resin, 1 part of zinc stearate was added as a scale agent, and 250 parts of silica powder was added as a filler. 1 in °C
The mixture was subjected to roll kneading for several minutes, cooled and pulverized to obtain the desired epoxy resin composition. This composition exhibits a shelf life of 5 to 7 days at room temperature, and when used in a specified mold,
When molded for 2 hours, it was completely cured to obtain an insoluble and infusible cured composition. Example 2 Two parts of 1-cyanoethyl-2-ethyl-4-methyl-imidazole was taken as an imidazole compound, and N-(3-chloro4methoxyphenyl)-N',N'-dimethylurea was added to it as an aromatic urea compound. 1 part of anchor was added and mixed uniformly to obtain a curing agent composition.

To the curing agent composition, 70 parts of a bisphenol type epoxy resin having an epoxy equivalent of 180 and 3 parts of an epoxy resin having an epoxy equivalent of 925 were added as epoxy resins to prepare Example 1.
The epoxy resin composition blended in the same manner as above had a shelf life of 5 to 7 days at room temperature, and when molded in the same manner as in Example 1, it was completely cured and the cured composition was infusible and infusible. Obtained. Example 3 2-undecyl-imidazole as an imidazole compound 8. 0.5 part of N-(4-chlorophenyl carbamoyl)piverizine was added as an aromatic urea compound and mixed uniformly to obtain a curing agent composition.

To the curing agent composition were added 50 parts of an epoxy resin with an epoxy equivalent of 180 and 50 parts of a novolac type epoxy resin with an epoxy equivalent of 178, and further 1 part of zinc stearate as a template agent and 20 parts of calcium carbonate as a filler. The potency time at room temperature of the product with the addition of anchorage was 5 to 7 days. When this epoxy resin composition was molded in the same manner as in Example 1, it was completely cured, yielding a non-curing cured composition. Example 4 8 parts of 2-ethyl-4-methyl-imidazole was taken as an imidazole compound, and N-(3,4-dichlorophenyl)-N',N'dimethylurea was added to it as a urea compound. In addition, 472-grade methyl ethyl ketone was dissolved and allowed to float at room temperature to obtain a uniform curing agent solution.

To 5 parts of the curing agent solution, 125 parts of an 8% by weight solution of epoxy resin with an epoxy equivalent of 255 in methyl ethyl ketone was added, and after mixing at room temperature, the solvent was removed under reduced pressure to form an epoxy resin composition. As a result, the expedient time at room temperature was 5 to 7 days. When this resin composition was molded using a predetermined mold in the same manner as in Example 1, it was completely cured to obtain an insoluble and infusible cured composition. Example 5 6.0 parts of 1-cyanoethyl-2-methyl-imidazole was taken as an imidazole-based compound, 5 times the mole of hydroquinone was added as an aromatic dibasic acid, and further N-(3 ,4-dichlorophenyl)-
Add 0.5 part of N',N'-dimethyl urea to 50 qo.
The mixture was uniformly mixed to obtain a curing agent composition.

To the curing agent composition was added 10 parts of an epoxy resin having an epoxy equivalent of 475, and 1 part of zinc stearate was added as a mold release agent.
After adding 25 parts of silica powder and 25 parts of silica powder as a filler,
Roll kneading was performed for 10 minutes at 0 qo, followed by cooling and pulverization to obtain the desired epoxy resin composition. This composition exhibits a shelf life of 7 to 10 days at room temperature, and has a shelf life of 130 days using a designated mold.
When molded for 0.02 hours, it was completely cured and an insoluble and infusible cured composition was obtained. Example 6 1 part of 2-ethyl-4-methyl-imidazole was taken as an imidazole compound,
To this, an equimolar amount of benzoic acid was added as an aromatic monobasic acid, and 10 parts of N-(3-chloro-4-methylphenyl)-N',N'-dipropylurea was added as a third component, and the mixture was heated to 6,000 ml. A curing agent composition was obtained by mixing.

Seven parts of an epoxy resin having an epoxy equivalent of 180 and 30 parts of an epoxy resin having an epoxy equivalent of 92.5 were added to the curing agent composition to prepare an epoxy resin composition in the same manner as in Example 1. was 5 to 10 days, and when molded in the same manner as in Example 1, it was completely cured and an insoluble and infusible cured composition was obtained. Example 7 2-undecyl imidazole as an imidazole compound3. To this, 4 times the mole of phthalic acid was added as an aromatic dibasic acid, and then N-(
4.0 parts of 3-chloro-4-methoxyphenyl)-N',N'-dimethylurea was added and mixed uniformly at room temperature to obtain a curing agent composition.

Epoxy resin with an epoxy equivalent of 180 to the curing agent
Novolac type epoxy resin with 178 parts and epoxy equivalent weight 5
The pot life at room temperature of a resin composition to which anchorage was added, 1 part of zinc stearate as a mold release agent, and 20 parts of calcium carbonate as a filler was 7 to 10, and this was used as an example. As a result of examination in the same manner as in 1, an insoluble and infusible cured composition was obtained. Example 8 Added 0.5 part of 1-cyanoethyl-2-ethylimidazole as an imidazole compound, added 3 times the mole of salicylic acid as an aromatic dibasic acid, and added N-(3,4-dichloro) as the third component. -phenyl)-N',N'
- Add 3 times as much dimethyl urea and 5 dollars of methyl ethyl ketone
The solution was dissolved and allowed to float at room temperature to obtain a uniform curing agent solution.

To the curing agent solution, 125 parts of an 8% by weight solution of epoxy resin with an epoxy equivalent of 255 in methyl ethyl ketone was added and mixed at room temperature, and then the methyl ethyl ketone was distilled off under reduced pressure to obtain an epoxy resin composition. The shelf life of the resin composition at room temperature was 10 to 14 days, and when it was molded in the same manner as in Example 1, a cured composition that did not disintegrate was obtained. Comparative Example 1 In Example 1, epoxy resin A (Epicoat 82&
Shell Chemical Co., Ltd.) 100 parts, 9 parts of 4,4'-diaminodiphenylsulfone, 3.27 parts of N-(3,4-dichlorophenyl)-N',N'-dimethylurea in 50q.
The mixture was mixed at once at o to obtain a composition (1).

When (1) is heat-treated at 10,000 ℃ and the viscosity triples, the reaction is stopped and the precondensate (0) is obtained.
After 130 qo and 30 minutes, the product remained cloudy and soft, and a sufficiently cured product could not be obtained. Moreover, its pot life was 3 days at 25 qo, which was extremely short. (b) contains a lot of methyl ethyl ketone insoluble matter, Example 1
It was not possible to obtain such a prepreg.

Comparative Example 2 In Example 1, epoxy resin A (Epicoat 828
, Shell Chemical, registered trademark) 100 copies USP 33869
Among the urea compounds described in the specification of No. 56, those that are highly effective when used alone are added as shown in Table 1 to make a paste.
After curing for 3 minutes at 30°C, the curing status was confirmed.

The results are also shown in Table 1. Table 1 Urea Materialism Fierce Battle) Relaxation ℃) N-(4-K.

. Phenyl) 3 Terminal cured - N', N diluted urea 5 〃 10 <600 15 <600 N・(phenyl) -N', N' - 3 Uncured diminutive urea 5'' 10 <600 15 <600 N -(4-Methylevenyl) 3 Uncured-N,N-dimethyleneurea 5'' 10 <600 15 <600 N-(4-methogynphenyl) 3 Uncured-N,N-dimethyleneurea 5'' 10 <600 15 < 600

Claims (1)

[Claims] 1. One or more imidazole compounds and one or more aromatic urea compounds represented by the general formula below ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (X and Y = -Cl , -Br, -CH_3, -NO_
2, -H, -OC_2H_5 or -OCH_3R_1 and R_2 = alkyl group, allyl group (ary1), alkoxy group, alkenyl group or aralkyl group, or R
A curing agent for epoxy resin, characterized in that it consists of (representing an alicyclic compound containing both _1 and R_2). 2 One or more imidazole compounds and one or more aromatic urea compounds represented by the following general formula ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (X and Y = -Cl, -Br, -CH_3 , -NO_
2, -H, -OC_2H_5 or -OCH_3R_1 and R_2 = alkyl group, allyl group, alkoxy group, alkenyl group, or aralkyl group, or R_1 and R_
Represents an alicyclic compound containing 2 at the same time. ) and 0.5 to 6.0 for the imidazole compound
A curing agent for epoxy resin, characterized in that it contains one or more aromatic monobasic acids or aromatic dibasic acids in twice the molar amount.