JP2622147B2 - Epoxy resin composition - Google Patents

Description

The present invention relates to a novel and useful epoxy resin composition, and more particularly to the use of an aromatic amine resin represented by the formula (I) as an essential curing component. Heat resistance, consisting of
The present invention relates to a resin composition having excellent impact resistance and suitable for applications such as casting, adhesion, lamination, and molding.

[Conventional technology]

Many compounds that have been used as curing agents in conventional epoxy resin compositions for such applications are known. For example, diethylenetriamine, isophoronediamine, metaxylenediamine, metaphenylenediamine, 4,4'-methylenediamine, 4,4'-diaminodiphenylsulfone and the like, aromatic amine compounds, phthalic anhydride, trimellitic anhydride, Pyromellitic anhydride,
Acid anhydrides such as maleic anhydride; phenolic resins such as phenol novolak resins; and other polyamides, imidazoles, and modified polyamines.

However, these compounds were converted to 2,2- (4-hydroxyphenyl) propane, phenol novolak resins,
When used as a curing agent for an epoxy resin derived from ortho-cresol novolak resin, 4,4'-methylenedianiline, etc., the epoxy resin composition has advantages and disadvantages in performance and has reached a satisfactory level. Not. That is, when used as a curing agent such as a matrix resin for a heat-resistant composite material or a heat-resistant adhesive, the above-mentioned conventional curing agent can no longer meet recent high performance requirements.

Heat-resistant composite materials, heat-resistant adhesives, and the like are required to withstand instantaneous impacts such as stress concentration as external stress. For this reason, elastically deforming like rubber ideally attracts attention as an important factor. As a criterion for determining such elastic deformation, the elongation at break of the matrix resin is particularly important. The greater the elongation of the matrix resin, the more the drawbacks of reinforcing agents such as glass fibers and carbon fibers required for composite materials can be compensated. That is,
The overall strength of the composite material is improved.

Generally, in these fields, it is determined whether heat resistance is mainly used and impact resistance is dependent, or impact resistance is adopted even if heat resistance is sacrificed.
At present, almost no epoxy resin composition that satisfies both the impact resistance and the heat resistance has been known.

In recent years, in order to impart flexibility, a method of adding polyethylene glycol, polypropylene glycol, or the like, a dispersed rubber particle phase is formed in a resin matrix, and the energy absorption at the time of fracture is increased by a sea-island structure. There are ways to accomplish this.

Even in these methods, problems such as remarkable decrease in heat resistance, workability, and reproducibility arise.

Furthermore, in heat-resistant composite matrix resins and heat-resistant adhesives, heat resistance and impact resistance as well as stability at long-term operating temperatures are important, and deterioration by light and oxygen in the air is small. Is also required. This oxidation resistance is mainly derived from the structure of the resin, and it is difficult to overcome various drawbacks caused by structural defects with a conventional curing agent, in addition to the requirement of the thermal and mechanical strength. there were.

[Means for solving the problem]

However, in view of such a situation, the present inventors have intensively studied a resin composition having further improved impact resistance without impairing the heat resistance as compared with conventional epoxy resin compositions.

As a result, the formula (I) (However, n in the formula represents an integer of 0 to 50.) The resin composition comprising an aromatic amine resin represented by the following formula as an essential curing agent component and, if necessary, a curing accelerator is further added. The present inventors have found that the present invention has such performances, and have completed the present invention.

That is, the present invention relates to an epoxy resin composition comprising an epoxy resin, a curing agent and, if necessary, a curing accelerator, wherein the curing agent comprises an aromatic amine resin represented by the above formula (I) as an essential component. The present invention provides an epoxy resin composition excellent in heat resistance and impact resistance comprising 10 to 50% by weight in all epoxy resin components.

Here, the aromatic amine resin has been newly discovered by the present inventors, and in particular, Japanese Patent Application Nos. 62-252517 and 62-282048.
No. was filed as an issue.

It consists of aniline and α, α′-dihalogeno-p-xylene, α, α′-dihydroxy-p-xylene, α, α
It is produced by reacting a p-xylylene compound such as α'-dialkoxy-p-xylene and α, α'-diasiloxy-p-xylene in the presence of an acid catalyst.

Specifically, the reaction is carried out in the range of 1 to 15 moles, preferably 1.1 to 10 moles of aniline per mole of the p-xylylene compound. Hydrochloric acid, sulfuric acid, etc. are used as the acid catalyst, and the temperature is 20 to
The condensation reaction is performed at 240 ° C. for 1 to 50 hours. Thereafter, the mixture is neutralized with an alkali such as a caustic soda aqueous solution, and unreacted aniline is recovered under reduced pressure to obtain an aromatic amine resin represented by the formula (I). The molecular weight range of the aromatic amine resin obtained by this method is about 300 to 5,000, and the softening point of the resin is liquid at room temperature to about 150 ° C. (ring and ball method softening point according to JIS-K-2548).

As long as this aromatic amine resin is used as an essential component of the epoxy resin composition of the present invention, it may be used in combination with other components as a curing agent. Examples of the other curing agents include the known curing agents listed above.

When the epoxy resin composition of the present invention is used in combination with various curing agents in order to impart high heat resistance and excellent impact resistance, the aromatic amine resin represented by the formula (I) may be used in an amount of 15 to A formulation comprising 100% by weight, preferably 30 to 100% by weight, is required.

As described above, by using the aromatic amine resin of the present invention as a curing agent and incorporating it into an epoxy resin composition, it has excellent impact resistance without impairing heat resistance, and has a high thermal decomposition onset temperature. This is due to the introduction of a p-xylene bond to a conventional methylene bond.

In preparing the composition of the present invention, first, as described above, the aromatic amine resin of the formula (I) is used as an essential component, and if necessary, another curing agent is used in combination with the epoxy resin.

This epoxy resin is usually the most common 2,2
Epoxy resin obtained by reacting -bis (4-hydroxyphenyl) propane and epihalohydrin, epoxy resin obtained by reacting phenol novolak resin and epihalohydrin, epoxy resin obtained by reacting orthocresol novolak resin and epihalohydrin,
Epoxy resins obtained by reacting 4,4'-methylene dianiline with epihalohydrin are preferred, and epoxy resins obtained from phenol aralkyl resins and epihalohydrins (Japanese Patent Publication No. 47-13782, Japanese Patent Application No. 62-70281)
Epoxy resin obtained from resorcin aralkyl resin and epihalohydrin (Japanese Patent Publication No. 47-13782, Japanese Patent Application No.
No. 2-233751) is still more preferable.

In preparing the resin composition of the present invention, if necessary, a curing accelerator, and if necessary, various known and commonly used additives such as a filler, a coloring agent, a flame retardant, a release agent or a coupling agent are added and blended. can do.

[Action]

By using the curable resin composition of the present invention thus obtained, a very useful matrix resin or adhesive for a composite material having excellent heat resistance and flexibility can be provided.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

Synthesis Example 1 (Preparation of aromatic amine resin) In a reaction vessel equipped with a stirrer, a thermometer, and a Dean-Stark azeotropic distillation trap, 1116 g (12 mol) of aniline was added.
665 g (4 mol) of α, α'-dimethoxy-p-xylene and 626 g (6 mol) of a 35% hydrochloric acid aqueous solution as a catalyst were charged, and the temperature was raised while passing nitrogen gas. Since the internal temperature was about 110 ° C, water distilled in the trap was removed from the system. When the temperature was further raised, methanol distilling was observed from about 130 ° C,
Continue elevating the temperature while distilling off the generated methanol,
After reaching ° C., it was kept constant for 3 hours. The generation of methanol almost disappeared, and the temperature was subsequently raised to 190
The reaction was carried out at a temperature between 200C and 200C for 12 hours. Next, the mixture was cooled to lower the internal temperature to 95 ° C., and 1680 g of a 15 ° C. aqueous solution of caustic soda was added thereto, followed by neutralization with stirring. After standing, the lower aqueous layer was separated and removed, and 3,000 g of saturated saline was added to perform washing and separation.
Next, after heat dehydration was performed under a nitrogen stream, pressure filtration was performed to remove inorganic salts and the like. This was concentrated in vacuo under a vacuum of 2-3 mmHg to recover 519 g of unreacted aniline. The residue was discharged to obtain 945 g of a light tan aniline resin.

The aromatic amine resin of the present invention obtained as described above,
As a result of composition analysis by high performance liquid chromatography,
In the general formula (I), n = 0 is 28, n = 1 is 16.8, and n = 2 is 1
0.5, n = 3 was 7.8, and n ≧ 4 was 36.9% (area%).

The amine equivalent of this resin (perchloric acid-glacial acetic acid method)
Was 0.578 equivalents / (100 g), and the softening point measured by a ring and ball method softening point measuring apparatus according to JIS-K-2548 was 68 ° C.
Further, the average molecular weight was 960.

Synthesis Example 2 (Preparation of aromatic amine resin) 931 g (10 mol) of aniline was placed in the same reactor as in Synthesis Example 1.
175 g (1 mol) of α, α'-dichloro-p-xylene was charged, and the temperature was raised while passing nitrogen gas. Heat generation was observed from the internal temperature of about 30 ° C, but the temperature was raised as it was to 70-80 ° C
For 5 hours. Next, 31.3 g (0.3 mol) of a 35% hydrochloric acid aqueous solution was charged into the reaction solution, and the temperature was raised as it was.

The water distilled off during the distillation was distilled out of the system. Temperature 20
The reaction was carried out at 0 to 205 ° C for 16 hours. Then, post-treatment was performed in the same manner as in Synthesis Example 1 to obtain a light yellow oily aniline resin.
As a result of analyzing the composition of the resin by high performance liquid chromatography, n = 0 in the formula (I) was 76, n = 1 was 19,
n = 2 was 4 and n ≧ 3 was 1% (area%).

The amine equivalent of this resin was 0.653 / (100 g), and the average molecular weight was 350.

Examples 1 to 8 If necessary, the aromatic amine resin obtained in the synthesis example was used as a curing agent for various epoxy resins.
Various additives were also blended, and a blend melt-kneaded at 100 ° C. was obtained. This composition was cured at 120 ° C for 2 hours,
Further post-curing was performed at 170 ° C. for 2.5 hours. Various properties of the thus obtained cured products were measured.

The results and formulations are summarized in Table 1.

 The following epoxy resin was used.

(A) Epoxy resin derived from 2,2-bis (4-hydroxyphenyl) propane; trade name Epikote 828 (manufactured by Yuka Shell Chemical, epoxy equivalent: 189) (B) Epoxy resin derived from phenol novolak resin; Trade name DEN-431 (Dow Co., epoxy equivalent 179) (C) Epoxy resin derived from ortho-cresol novolak resin; Trade name EOCN-102S (Nippon Kayaku, epoxy equivalent 218) (D) 4,4 ' -Epoxy resin derived from methylene dianiline; trade name Araldite MY 720 (Ciba-Geigy, epoxy equivalent 122) (E) α, α in a reaction vessel equipped with a stirrer, temperature system, and Dean-Stark azeotropic distillation trap '-Dimethoxy-p-xylene 250 g (1.5 mol), phenol 847 g (9.0
Mol), and 1.1 g of paratoluenesulfonic acid,
Stirring was continued while maintaining the mixed solution at 130 ° C to 150 ° C. During the reaction, generated methanol was sequentially removed from the system through the trap.

After 3 hours, no methanol was generated and the condensation was completed. Next, unreacted phenol was distilled under reduced pressure to obtain 393 g of a phenol aralkyl resin composition having a structure of the general formula (II).

As a result of measuring the composition of the obtained resin by high performance liquid chromatography, n = 0 was 60.3, n = 1 was 24.3, and n = 2.
Is 9.2, n = 3 is 3.8, and n ≧ 4 is 2.4% (area%)
Met.

393 g of this resin and 1100 g (11.9 mol) of epichlorohydrin were mixed and charged into a reaction vessel equipped with a stirrer, a Dean-Stark azeotropic distillation trap, and a dropping funnel.

The mixture was heated to 115-119 ° C. while stirring, and 275 g of 40% aqueous sodium hydroxide solution was added dropwise at the same temperature in 4 hours. Distilled water was continuously separated and recovered, and the epichlorohydrin phase was set in the reactor. Back to. After the completion of the dropwise addition, the reaction is terminated by removing the distilled water.

Thereafter, excess epichlorohydrin was distilled under reduced pressure, the reaction product was dissolved in 1500 g of methyl isobutyl ketone (MIBK), sodium chloride and a small excess of sodium hydroxide were filtered, and the solvent was distilled off under reduced pressure to obtain a yellow oil. 465 g of an epoxy resin was obtained.

The epoxy equivalent was 227 g / eq, and the viscosity (by an E-type viscometer manufactured by Tokyo Keiki) was 468 g / cm · sec (35 ° C.).

(F) In a reaction vessel equipped with a stirrer, a thermometer, and a Dean-Stark azeotropic distillation trap, 250 g (1.5 mol) of α, α'-dimethoxy-p-xylene and 1650 g of resorcinol (15 mol)
Mol), and 8.3 g of paratoluenesulfonic acid,
The mixed solution was stirred while being kept at 130 ° C to 150 ° C. During the reaction, generated methanol was sequentially removed from the system through the trap. After 3 hours, no methanol was generated and the condensation was completed. Next, the mixture was cooled to 50 to 60 ° C., charged with 3000 g of methyl isobutyl ketone and dissolved therein, further charged with 1000 g of water, stirred at 50 to 60 ° C. for 30 minutes, then stopped stirring, allowed to stand, and separated (upper layer: organic layer). / Lower layer: water layer), and the water layer was discharged, and the water washing was completed. Then, methyl isobutyl ketone and unreacted resorcinol are distilled off under reduced pressure, and 385 g having a structure of the general formula (III) is obtained.
Was obtained. As a result of measuring the composition of the obtained resin by high performance liquid chromatography, n = 0 was 63.0, n = 1 was 21.2, n = 2 was 9.1,
Those with n ≧ 3 were 6.7% (area%). The softening point (according to JIS-K-2548) of this resin was 75 ° C.

385 g of this dihydric phenol aralkyl resin and 1100 g (11.9 mol) of epichlorohydrin were mixed and charged into a reaction vessel equipped with a stirrer, a Dean-Stark azeotropic distillation trap and a dropping funnel. The mixture is stirred for 115 minutes.
After the temperature was raised to about 119 ° C., 550 g of a 40% aqueous sodium hydroxide solution was added dropwise over 4 hours at the same temperature. The distilled water was continuously separated and collected, and the epichlorohydrin phase was returned to the reactor.
After the completion of the dropwise addition, the reaction is terminated by removing the distilled water. Thereafter, excess epichlorohydrin was distilled under reduced pressure, the reaction product was dissolved in 1500 g of methyl isobutyl ketone, sodium chloride and a small excess of sodium hydroxide were filtered, and then the solvent was distilled off under reduced pressure to obtain an orange-colored epoxy resin. To 44
5 g was obtained.

The epoxy equivalent was 159 g / eq, and the softening point of this resin was 42 ° C.

Comparative Example 1.2 Epoxy resins (A) and (D) were added with a curing agent of 4,4 ′
Various properties were measured in the same manner as in the examples using methylene dianiline (DDM).

The results and formulations are summarized in Table 1.

(Note in Table 1) Epoxy resin (A) Epicoat 828 (Yuka Kadiel,
Epoxy equivalent 189) Epoxy resin (B) DEN-431 (Dow, Epoxy equivalent 179) Epoxy resin (C) EOCN-102S (Nippon Kayaku, Epoxy equivalent 218) Epoxy resin (D) Araldite MY-720 (Ciba-Geigy) Epoxy resin (E) 122) Epoxy resin (E) Phenol aralkyl resin epoxidized product (synthetic product, epoxy equivalent 227) Epoxy resin (F) Resorcin aralkyl resin epoxidized product (synthetic product, epoxy equivalent 159) DDM 4,4'-methylene dianiline DDS 4,4'-diaminodiphenylsulfone TAP 2,4,6-tris (dimethylaminomethyl) phenol BF ₃ -C ₂ H ₅ NH ₂ boron trifluoride-ethylamine complex ED-506 polypropylene glycol diglycidyl ether ( Asahi Denka, epoxy equivalent 300-340) Gelling time According to JIS K-6910.

Heat deformation temperature According to JIS K-7207.

Bending test According to JIS K-7203.

Tensile test According to JIS K-7113.

〔The invention's effect〕

As described above in detail, in the resin composition using the aromatic amine resin represented by the formula (I) as a curing agent for various epoxy resins, excellent heat resistance, impact resistance and thermal stability have been confirmed. Was. Such a resin composition can be used for highly heat-resistant materials such as a matrix resin for heat-resistant composites, a heat-resistant adhesive, and a heat-resistant paint, which have been strongly demanded in recent years, and greatly contributes to the advanced industrial field.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-123828 (JP, A) JP-A-1-95125 (JP, A) JP-A-59-215315 (JP, A) JP-A-63-1988 250351 (JP, A) JP-A-62-263218 (JP, A) JP-A-61-40318 (JP, A) JP-A-60-228528 (JP, A) JP-A-64-74226 (JP, A) JP-B-46-19186 (JP, B1) JP-B-52-14280 (JP, B2)

Claims (2)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent and, if necessary, a curing accelerator, wherein the curing agent has the formula (1) (However, n in the formula is an integer of 0 to 50.) An aromatic amine resin represented by the following formula, which is an essential component, contains 10 to 50% by weight in all epoxy resin components, and has excellent heat resistance and impact resistance. Epoxy resin composition. 2. Epoxy resin is 2,2-bis (4-hydroxyphenyl) propane, phenol novolak resin, orthocresol novolak resin, 4,4'-methylene dianiline, formula (II) (Where n represents an integer of 0 to 50), a phenol aralkyl resin represented by the formula (III): The heat resistance and the impact resistance according to claim 1, wherein the polyfunctional epoxy resin is obtained by reacting epihalohydrin with any one of resorcin aralkyl resins represented by the formula (where n represents an integer of 0 to 50). Excellent epoxy resin composition.