JPH07224148A - Heat-resistant epoxy resin composition excellent in stability at normal temperature - Google Patents

Abstract

PURPOSE:To obtain the subject composition, comprising a specific epoxy compound, an imidazole-based compound and an aromatic sulfonic acid compound, etc., having a long pot life at normal temperature, capable of rapidly carrying out the hot curing reaction, good in molding processability and providing a cured resin excellent in heat distortion resistance. CONSTITUTION:This composition comprises (A) a polycyclic or adjacent plural monocyclic epoxy compound having >=2 epoxy groups in the molecule or a monocyclic epoxy compound having >=3 epoxy groups in the molecule, (B) an imidazole-based compound expressed by formula I (R1 is H or 2,4-diamino-3,5- triazino-6-ethyl group; R2 is an aliphatic, an aromatic or an alicyclic group; R3 is N, an aliphatic group or a hydroxyalkyl; R4 is H or a hydroxyalkyl) and (C) an aromatic sulfonic acid compound and/or a boric acid ester compound expressed by formula II (R5 to R7 each is an aliphatic, an aromatic or an alicyclic group) as principal components.

Description

Detailed Description of the Invention

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant epoxy resin composition having excellent stability at room temperature, and more specifically, it has a long pot life at room temperature, and has excellent heat distortion resistance and heat deterioration resistance. The present invention relates to an excellent epoxy resin composition.

[0003]

2. Description of the Related Art As a raw material for a heat-resistant epoxy resin, a polycyclic or monocyclic polyfunctional epoxy compound such as naphthalenediol type, α-naphthol type, biphenyl type, etc., which has a short distance in the epoxy group in the molecule, has attracted attention. ing. However, since most of these heat-resistant epoxy compounds are solids or high-viscosity liquids at room temperature, when one-part epoxy compounding is performed, the epoxy compound is dissolved in another low-viscosity epoxy compound having high solubility and used. There is a need.

Therefore, when a general amine compound is used as a curing material, the amine compound easily dissolves in the above-mentioned low-viscosity epoxy compound having a high dissolving power, so that the room temperature stability of the composition is deteriorated. Further, most of amine compounds which are difficult to dissolve in the low-viscosity epoxy compound have good stability at room temperature when used, but their heat curing reaction is extremely slow, and they are poor in practicality. That is, by using a polycyclic or monocyclic polyfunctional epoxy compound having a short distance between epoxy groups in the molecule and having good heat resistance at room temperature and a long pot life, the curing reaction is fast and the molding process is performed. It has been desired to develop a new one-pack type epoxy resin composition having a short time and a cured resin obtained having excellent heat distortion resistance and heat deterioration resistance.

[0005]

SUMMARY OF THE INVENTION The present invention aims to provide a one-component epoxy resin composition having excellent stability at room temperature and high heat resistance of a cured resin. By adding a specific amine-based curing agent and a novel room temperature curing inhibitor to this polyfunctional epoxy compound, the pot life is long, the heat curing reaction is fast, and the molding processability is good. Is to provide a novel one-pack type epoxy resin composition which is excellent in heat distortion resistance and low heat deterioration resistance.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a polycyclic or adjacent plural monocyclic epoxy compound having two or more epoxy groups in a molecule, or a monocyclic epoxy compound having three or more epoxy groups in a molecule. An epoxy compound containing a compound,
General formula

[Chemical 1] (In the formula, R ₁ is hydrogen or 2,4-diamino-1,3,3.
5-triazino-6-ethyl group, R ₂ represents an aliphatic group, an aromatic group or an alicyclic group, R ₃ represents hydrogen or an aliphatic group or a hydroxyalkyl group, and R ₄ represents hydrogen or a hydroxyalkyl group. ) And an aromatic sulfonic acid compound and / or a general formula

[Chemical 2] (In the formula, R ₅ , R ₆ and R ₇ represent an aliphatic group, an aromatic group or an alicyclic group.) The present invention relates to an epoxy resin composition containing a borate ester compound represented by the formula. The present inventors arrived at the present invention as a result of earnest research to obtain an epoxy resin composition that has good stability at room temperature, a long pot life, a fast curing reaction when cured, and a cured product with excellent heat resistance. did.

The epoxy compound used in the present invention must have a rigid skeleton among those having an aromatic ring, and must be a heat-resistant hard epoxy resin. Epoxy compounds that satisfy these requirements include polycyclic or adjacent plural monocyclic epoxy compounds having a short distance between epoxy groups in the molecule, or epoxy compounds having three or more epoxy groups in the molecule. A monocyclic epoxy compound having a group is preferable, and typically, phenol novolac polyglycidyl ether, O-cresol novolac polyglycidyl ether, bromophenol novolac polyglycidyl ether, and tetraglycidyl m.
-Xylene diamine, tetraglycidyl diaminodiphenylmethane, α-naphthol polyglycidyl ether,
Furthermore, Nippon Kayaku Co., Ltd.'s EPPN-502, Dainippon Ink and Chemicals Inc.'s HP-4032, Nippon Steel Chemical Co., Ltd.
ESN-365 etc. made from can be mentioned.

Since these epoxy compounds are solid or high-viscosity liquid at room temperature, they are used by dissolving them in other low-viscosity epoxy compounds having high dissolving power. Examples of low-viscosity epoxy compounds that can be used include bifunctional epoxy compounds such as bisphenol A diglycidyl ether having an epoxy equivalent of 500 or less, bisphenol F diglycidyl ether having an epoxy equivalent of about 180, and diglycidyl aniline, and further phenylglycidyl ether. Monofunctional epoxy compounds such as can also be used in combination with these bifunctional epoxy compounds.

In order to achieve the object of the present invention, the curing agent needs to be one which does not easily dissolve in the epoxy compound used in the present invention at room temperature and has a rapid heat curing reaction. As a result of various investigations, the inventor has found that

[Chemical 1] (In the formula, R ₁ is hydrogen or 2,4-diamino-3,5-
Triazino-6-ethyl group, R ₂ is an aliphatic group, an aromatic group or an alicyclic group, R ₃ is a hydrogen atom, an aliphatic group or a hydroxyalkyl group, and R ₄ is a hydrogen atom or a hydroxyalkyl group. ) Is an imidazole compound. As a specific example of the imidazole compound used in the present invention, the structural formula is

[Chemical 3] 1- (2,4-diamino-1,3,5-triazino-
6-ethyl) -2-methylimidazole, having the structural formula

[Chemical 4] 2-phenyl-4methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-benzylimidazole, 2-cyclohexyl-4,5-dihydroxymethylimidazole, etc. . Further, 2-methylimidazole / isocyanuric acid adduct, 1-cyanoethyl-2-phenylimidazole / trimellitic acid adduct and the like can be used.

As a result of various studies to extend the pot life at room temperature of the main component containing a heat-resistant epoxy compound and a heat-resistant epoxy resin composition containing an imidazole compound as a curing agent, aromatic sulfonic acid compounds and boric acid esters were obtained. It has been found that the compounds are very effective as room temperature cure inhibitors. Specific examples of the aromatic sulfonic acid compound used in the present invention include p-toluenesulfonic acid (CH ₃ · C).
_{6 H 4 SO 3 H · H} 2 O), p- toluenesulfonic acid _{(CH 3 · C 6 H 4} SO 3 H · H 2 O), p- toluenesulfonic acid ethyl ester _{(CH 3 C 6 H 4 SO} 3 C ₂
H _5), p-toluenesulfonic acid sodium salt (CH _{3
· C 6 H 4 SO 3 Na} ), 8- hydroxyquinoline -5
- sulfonic acid _{(C 9 H 7 NO 4 S} · H 2 O), pyridine-3-sulfonic acid _{(C 5 H 4 NSO 3 H} ) can be mentioned, such as the general formula

[Chemical 2] In the boric acid ester compound represented by, examples of the aliphatic group include methyl (CH ₃ ) ethyl (CH ₃ CH ₂ ), n-
Propyl (CH ₃ CH ₂ CH ₂ ), isopropyl ((C
H _{3) 2} CH), n- octadecyl _(CH 3 _(CH 2)
₁₇ ) and the like, examples of aromatic groups include phenyl (C ₆
H ₅ ), benzyl (C ₆ H ₅ .CH ₂ ), nucleus-substituted phenyl, naphthyl, and the like. Examples of the alicyclic group include cyclohexyl, cyclopentadienyl, and the like. Suitable are boric acid ester, tributyl boric acid ester, triphenyl boric acid ester and the like. By adding these aromatic sulfonic acid compounds and / or boric acid ester compounds, the curing reaction at room temperature can be suppressed and the pot life can be lengthened. That is, the epoxy compound 10 used in the present invention
By adding 0.5 to 5.0 parts by weight to 0 parts by weight, the heat-resistant epoxy resin composition of the present invention comprising the epoxy compound used in the present invention and an imidazole compound can be used at room temperature. The time can be greatly extended.

These aromatic sulfonic acid compounds and boric acid ester compounds have the effect of suppressing the curing reaction at room temperature, and have the effect of promoting the curing reaction by heating at 100 ° C. or higher, but further accelerate the curing and stabilize them. A curing accelerator can be used in combination to obtain the usable pot life. As a curing accelerator, orotic acid (C ₅ H ₄ N ₂ O
₄ · _H 2 O), anthraquinone _{(C 14 H 8 O 2)} , phenothiazine _{(C 12 H 9 NS),} 3- (3,4- dichlorophenyl) -1,1-dimethylurea _(C 12 _C 6 H
_{3 NHCON (CH 3) 2)} , 5,5- dimethyl human Zant in _{(C 5 H 8 N 2 O} 2), various amino acids such as can be used.

Therefore, the aromatic sulfonic acid compound and the boric acid ester compound act as a curing accelerating agent when suppressing the curing reaction at room temperature and curing by heating at the same time. Therefore, the epoxy resin composition of the present invention is epoch-making. Additive.

As described above, the heat-resistant epoxy compound and the general formula

[Chemical 1] The epoxy resin composition containing an imidazole-based compound represented by, and an aromatic sulfonic acid compound or a boric acid ester compound has a long pot life, and the heat curing reaction is fast, the moldability is good, and the cured resin is excellent. Provides heat distortion resistance. Further, the cured resin from the epoxy resin composition is also excellent in heat deterioration resistance, but the heat deterioration resistance can be further greatly improved by mixing ceramic whiskers or organic or inorganic fibers. The ceramic type whiskers used in the present invention include silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), potassium titanate (K ₂ O.6).
TiO ₂ ), aluminum borate (9Al ₂・ 2B ₂ O
₃ ) and calcium sulfate (CaSO ₄ ), etc.,
As the organic or inorganic fiber, for example, aramid fiber,
Examples thereof include glass fiber and carbon fiber. The addition amount can be changed depending on the viscosity of the resin composition, but the epoxy compound 10
5 to 30 parts by weight is suitable for 0 parts by weight.

[0014]

The present invention will be described with reference to the following examples, but the scope of the present invention is not limited by these examples. The correspondence between the abbreviations used in the examples and the substance names is as follows.

A. Epoxy compound: 1. ESN-365; Naphthalenediol-based polyglycidyl ether having an epoxy equivalent of 165 2. HP-4032; naphthalene diol type polyglycidyl ether having an epoxy equivalent of 149; EPPN-502; aromatic monocyclic polyglycidyl ether having an epoxy equivalent of 166 4. Epicoat 828; Bisphenol A diglycidyl ether with an epoxy equivalent of about 190 5. GAN; Epoxy equivalent 125-145
Diglycidyl aniline 6. PGE; Phenylglycidyl ether

B. Imidazole-based compound: 1.2P4MHZ; 2-phenyl-4-methyl-5-hydroxymethylimidazole 2.2MZ-AZINE; 1- (2,4-diamino-
1,3,5-triazino-6-ethyl) -2-methylimidazole

C. Aromatic sulfonic acid compound: 1. p-TSA; p-toluenesulfonic acid 2. HQSA; 8-hydroxyquinoline-5
-Sulfonic acid

D. Borate ester compound: 1. (PhO) ₃ B; triphenyl borate ester 2. (BuO) ₃ B; Tributyl borate ester

E. Curing accelerator: 1. DCPDU; dichlorophenyldimethylurea 2. ANQN; Anthraquinone

F. Ceramic-based whiskers and powders: 1. SiC; Silicon carbide whiskers 2. TISMO-N; Calcium titanate whiskers 3. Arborex; Aluminum borate whiskers 4. Silica; fused silica powder

The epoxy resin composition was evaluated as follows. 1. Pot life (P-Time) A sample was put in a high temperature tank at a predetermined temperature (40 ° C), and the number of days until the fluidity disappeared was measured. Generally, 40 ℃ ・ 5 days is 25 ℃ ・ 12 ~ 13 days, 40 ℃ ・ 21 days is 25 ℃ ・ about 1
At 80 ° C, 40 ° C for 25 days is equivalent to 25 ° C for about 200 days.

2. Glass transition temperature (Tg · ° C.) As an index of heat distortion resistance, Tg was measured using a thermomechanical analyzer for a sample cured at a predetermined temperature for a predetermined time. Temperature rising rate: 10 ° C / minute load: 10g Needle diameter: 1mm

3. Evaluation of heat deterioration resistance: Cracks, carbonization, etc. were observed by placing the sample in a high temperature tank at a predetermined temperature. The time until changes such as cracking and carbonization occurred was measured. The cured samples in the examples were prepared by two-stage curing including initial curing and post-curing. Each is shown by f-Cure and p-Cure.

[0024]

Example 1 ESN-365, which is solid at room temperature, is dissolved in a liquid mixture of Epicoat 828 and GAN by heating at about 80 ° C. to form a mixture of epoxy compounds, which is allowed to cool to room temperature and then a predetermined amount of a curing inhibitor is added. Dissolved. 2P4MHZ as a curing agent and a curing accelerator were made into a fine powder and mixed with this mixture of epoxy compounds. Five kinds of epoxy resin compositions having different compositions such as different curing inhibitors and addition of curing accelerators were prepared, and the pot life time at 40 ° C, the glass transition temperature and the heat deterioration resistance were measured. Table 1 shows the composition ratio and measured value of each composition. (The composition is parts by weight)

[Table 1] Composition-1 and composition-2 were at 180C for more than 180 days, composition-
Nos. 3 to 5 have a long pot life of 200 days or more. In addition, Tg ° C is very high at 232 to 246, and 5
A cured resin having excellent heat distortion resistance and heat deterioration resistance was obtained from all the compositions of the seeds.

[0025]

Example 2 A curing inhibitor was dissolved in a mixture of Hp-4032 and an epoxy compound of Epicoat 828, and then 2MZ-AZINE as a curing agent, which was fine powder, and a curing accelerator were mixed. Pot life time, Tg as in “Example 1”
C., heat deterioration resistance was measured. Table 2 shows the composition ratio and measured value of each composition. (The composition is parts by weight)

[Table 2] Pot life time at 40 ° C is 2 for all compositions
It was 6 months or more when converted to 25 ° C in one day or more.
It shows that the cured product is excellent in both heat distortion resistance and heat deterioration resistance.

[0026]

[Example 3] An epoxy resin composition containing a curing agent, a curing inhibitor and a curing accelerator was prepared in the same manner as in "Example 1" using a heat-resistant epoxy compound. A ceramic-based whisker was added to this resin composition with an epoxy compound 10
8 parts by weight was mixed with 0 part by weight. The resin composition, pot life time, and heat resistance are shown in Table-3. (The composition is parts by weight)

[Table 3] The addition of ceramic whiskers has little effect on the pot life at room temperature and the heat distortion resistance of the cured resin, but the heat deterioration resistance is greatly improved.

[0027]

Example 4 HP-403 as a heat-resistant epoxy compound
2. The effect of ceramic whiskers in a system using 2P4MHZ as a curing agent was investigated. An epoxy resin composition mixed with whiskers was prepared according to the method in “Example” 3. Table 4 shows the resin composition and heat deterioration resistance. (The composition is parts by weight)

[Table 4] Since SiC and TISMO-N are whiskers, they greatly improve the heat deterioration resistance, but since silica is a powder, there is almost no improvement in heat deterioration resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 63/00 NLB

Claims (2)

[Claims] 1. A polycyclic or adjacent monocyclic epoxy compound having two or more epoxy groups in a molecule or a monocyclic epoxy compound having three or more epoxy groups in a molecule, and a compound represented by the general formula: ] (In the formula, R ₁ is hydrogen or 2,4-diamino-3,5-
Triazino-6-ethyl group, R ₂ is an aliphatic group, an aromatic group or an alicyclic group, R ₃ is a hydrogen atom, an aliphatic group or a hydroxyalkyl group, and R ₄ is a hydrogen atom or a hydroxyalkyl group. ) And an aromatic sulfonic acid compound and / or a general formula: (Wherein R ₅ , R ₆ and R ₇ represent an aliphatic group, an aromatic group or an alicyclic group) as a main component, and heat resistance excellent in room temperature stability is contained. Epoxy resin composition. 2. A polycyclic or adjacent monocyclic epoxy compound having two or more epoxy groups in the molecule or a monocyclic epoxy compound having three or more epoxy groups in the molecule, and a compound represented by the general formula: ] (In the formula, R ₁ is hydrogen or 2,4-diamino-3,5-
Triazino-6-ethyl group, R ₂ is an aliphatic group, an aromatic group or an alicyclic group, R ₃ is a hydrogen atom, an aliphatic group or a hydroxyalkyl group, and R ₄ is a hydrogen atom or a hydroxyalkyl group. ) An imidazole compound represented by
Aromatic sulfonic acid compound and / or general formula (Wherein R ₅ , R ₆ and R ₇ represent an aliphatic group, an aromatic group or an alicyclic group) and a ceramic whisker as main components and stable at room temperature A heat resistant epoxy resin composition having excellent properties.