JPH0610249B2 - Epoxy resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition for a prepreg which provides excellent storage stability, resistance to humidity and heat, and compression after impact resistance. The obtained composite material can be used for aircraft, automobiles, and general industrial applications.

[Conventional technology]

Conventionally, epoxy resin has been widely used as a matrix resin for composite materials because of its adhesiveness and high rigidity. Among them, as a high performance structural matrix resin, a composition containing N, N, N ', N'-tetraglycidyl diaminodiphenyl methane and 4,4'-diaminodiphenyl sulfone as a main component is 197.
It has been widely used for two years.

[Problems to be solved by the invention]

However, the prepreg obtained from this composition had a problem in storage stability, and the shelf life at room temperature was limited to 14 days. The moisture and heat resistance was not sufficient, and the high temperature compressive strength after moisture absorption was significantly reduced. Further, since the elongation of the matrix resin is small, it cannot follow the recent high elongation reinforcing fibers such as carbon fibers, aramid fibers and glass fibers having a breaking elongation of 1.5% or more, and the tensile elongation is a reinforcing fiber. It had drawbacks such as being lower. Moreover, the compressive strength after impact was extremely low, and it was a material that was completely inadequate to be used as a primary structural material.

In view of the above, the present inventors have made diligent studies on an epoxy resin composition for prepreg that provides a composite material having excellent storage stability, moist heat resistance, high reinforcing material utilization ratio, and impact post-pressing pressure property, The present invention has been reached.

[Means for solving problems]

That is, the gist of the present invention is (A) a bifunctional epoxy resin (B) a trifunctional or higher functional epoxy resin (C) a phenol compound represented by the following formula (However, X _{1 to} X ₈ represent Br, Cl, H, 4 or more of which represent Br or Cl, and R ₁ and R ₂ represent H or CH ₃ , respectively.) (D) Dicyandiamide, 2,6-xyle Nilbiguanide,
An epoxy resin composition comprising at least one selected from the group consisting of O-tolyl biguanide, diphenyl guanidine, adipyl dihydrazide, azelayl dihydrazide, and isophthalic acid dihydrazide as an essential component.

Further, it is an epoxy resin composition containing reinforcing fibers in the above epoxy resin composition.

Examples of the (A) bifunctional epoxy resin used in the present invention include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and brominated epoxy resins thereof.
Examples thereof include bisphenol S type epoxy resin.

In order to improve the toughness, it is preferable to use a bisphenol A type epoxy resin or a bisphenol F type epoxy resin as a main component. The ratio of these components in the epoxy resin is 50 to 93% by weight, preferably 70% by weight.
~ 85%. If it is more than this range, the heat resistance is lowered and the chemical resistance is lowered, which is not preferable. On the other hand, if it is less than this range, the toughness elongation becomes insufficient, which is not preferable.

Examples of the trifunctional or higher functional epoxy resin (B) used in the present invention include glycidylamine type epoxy resins such as N, N,
N ', N'-tetraglycidyldiaminodiphenylmethane, N, N, O-triglycidyl-p- or m-aminophenol, 1,1,2,2- (tetraglycidyloxyphenyl) -ethane, 1, 1,1- (triglycidyloxyphenyl) methane, teroraglycidyl-4,4- (4-aminophenyl) -p-diisopropylbenzenphenol novolak type epoxy resin, cresol novolak type epoxy resin and the like can be mentioned.

Above all, 1,1,1- (triglycidyloxyphenyl) -methane, terraglycidyl-4,4- (4-aminophenyl) -p-diisopropylbenzene, tetraglycidyl
4,4- (4-amino-3,5-dimethylphenyl) -p-
Diisopropylbenzene is preferably used. The proportion of these components in the epoxy resin component is 50 to 7% by weight, preferably 30 to 12%. If it is used in excess, the toughness and elongation will be insufficient, and if it is less than this, water resistance, solvent resistance and heat resistance will be insufficient, which is not preferable.

In addition, N, N, O-triglycidyl-m is contained in the epoxy resin component.
It is effective to contain less than 10% by weight of -or-p-aminophenol, but it is not preferable to use more than this because the water resistance decreases.

Examples of the phenol compound (C) used in the present invention include tetrabromobisphenol A, tetrabromobisphenol F, octachrome bisphenol A, hexabromobisphenol A and the like.

Examples of the curing agent as the component (D) include dicyandiamide, adipic acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide.

Examples of the reinforcing fiber as the component (E) include carbon fiber, glass fiber, aramid fiber, boron fiber, and silicon carbide fiber.

The ratio of epoxy groups / phenol OH groups of (C) to epoxy resins (A) and (B) is preferably 1 / 0.2 to 0.7, and when the number of phenol OH groups is less than this, sufficient water resistance is obtained. Is not suitable because toughness cannot be obtained, and if it is more than this range, the degree of cross-linking decreases and heat resistance and solvent resistance decrease, which is not preferable. More preferably, it is 0.3 to 0.6.

On the other hand, the amount of (D) used relative to (A) (B) (C) is preferably (epoxy group-phenol group) × 0.5 to 1.0, which is equivalent to the amount of NH group. If it is less than 0.5, the curing will be insufficient and the solvent resistance and heat resistance will be poor.
If it is larger, the water resistance is lowered and the toughness is lowered, which is difficult.

The resin composition of the present invention contains, as other components, an inorganic filler such as silica powder, Aerosil, microballoons, antimony trioxide as a flame retardant, and a polyether sulfone having a terminal phenol for the purpose of controlling the flowability. It is also possible to use polyvinyl butyrate or the like together.

The reinforcing fiber can also be used in the form of milled fiber, chipped fiber, unidirectional sheet or woven fabric.

〔Example〕

The present invention will be specifically described below with reference to examples. Parts represent parts by weight.

Example 1 Bisphenol A diglycidyl ether (trade name: Epicoat 828, epoxy equivalent 182, Shell Chemical Co., Ltd.)
Manufactured) 85 parts, 1,1,1- (triglycidyloxyphenyl) methane (epoxy equivalent 153) 15 parts, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane 57 parts, dicyandiamide 6 parts of silicon oxide fine powder Aerosil380 (manufactured by Nippon Aerosil Co., Ltd.)
1.25 parts was added and mixed well by a kneader at 60 ° C. to obtain a resin composition (I). This composition was sandwiched between glass plates to form a 2 mm plate and cured at 180 ° C. for 2 hours to obtain a resin plate. Further, a carbon fiber "Pyrofil" M-1 (trademark of Mitsubishi Rayon Co., Ltd.) in which the resin composition (I) was aligned in one direction was impregnated by the hot melt method to have a basis weight of 145 g / m ^2.
A unidirectional prepreg having a resin content of 35% by weight was prepared.
This prepreg is [0 °] ₁₆ and [+ 45 ° / 0 ° /-
45 ° / 90 °] Laminated in _4S quasi-isotropic, and 2 at 180 ° C
It was cured for a time to obtain a composite agent. The test results for them are shown in Table 1.

The glass transition temperatures in Table 1 are based on a differential thermal analyzer (Perkin Elmer DSC-II type). The flexural properties of the resin are according to ASTM D-790. The storage torsional rigidity G'is measured by Rheometrics Inc. RDS-7700 dynamic mechanical spectrometer.

The hot water resistance of the composite material was measured by ASTM D-69 after the laminated material composite of 0 ° 16 layers was left in 71 ° C water for 14 days.
The compression test in the direction of 0 ° at 82 ° C.
As for impact resistance, in accordance with NASA RP1092, a plate with a panel size of 4 "x 6" is fixed on a stand with a hole of 3 "x 5", and a 1/2 "R nose is attached to the center of the plate. A weight of 9 kg was dropped, and an impact of 1500 lb.in per 1 inch of plate thickness was applied, and then the panel was subjected to a compression test. The storage stability of the resin is determined by the number of days until the composition loses flexibility. The MEK resistance was judged by the appearance change after the resin cured product had been soaked at room temperature for 7 days, and the one with no change was marked with O and the large one was marked with X. The water absorption was 95 ° C for 24 hours after immersion in warm water. It was calculated from the increase in weight.

Examples 2-5, Comparative Examples 1-6 Bisphenol A diglycidyl ether of Example 1, 1,
1,1- (triglycidyloxyphenyl) methane, 2,2
Table 1 shows the same experiment as in Example 1 except that the compounding ratio of -bis (3,5dibromo-4-hydroxyphenyl) propane and dicyandiamide was changed.

Examples 6-11, Comparative Examples 7-8 1,1,1- (triglycidyloxyphenyl) of Example 1
Instead of methane, tetraglycidyl-4,4- (4-aminophenyl) -p-diisopyribenzel, 1,1,2,2-
The same experiment was conducted by using (tetraglycidyloxyphenyl) -ethane and changing the compounding ratio, and the results are shown in Table 1.

Examples 12 to 14 and Comparative Example 9 Table 2 shows the results of experiments conducted by changing the amount of N, N, O'-triglycidyl-m-aminophenol in the system of Example 1.

Examples 15 to 16 Table 2 shows the results of experiments conducted by changing the phenol compound (C) and the curing agent (D) of the system of Example 1.

Comparative Example 10 100 parts of N, N, N ', N'-tetraglycidyl diaminodiphenylmethane as a resin component in Example 1, 4,
An experiment was conducted in the same manner as in Example 1 except that a mixture of 40 parts of 4'-diaminodiphenyl sulfone was used. The results are shown in Table 2.

Front page continuation (72) Takatoshi Kubo Inventor Takatoshi Kubo 20-1 Miyuki-cho, Otake-shi, Hiroshima Mitsubishi Rayon Co., Ltd. Inspector Yoko Nakajima (56) References JP-A-58-79009 (JP, A) JP-A-59- 155422 (JP, A) JP 55-69616 (JP, A) JP 57-187325 (JP, A) JP 58-167625 (JP, A)

Claims (1)

[Claims] 1. The following components (A), (B), (C) and (D) are contained as essential components, and the weight ratio of (A) / (B) is 50-93 / 50-7, (C). Usage is (A) (B)
The ratio of the epoxy group of / the phenolic OH group of (C) is 1 /
The amount is in the range of 0.2 to 0.7, and the amount of (D) used is less than the epoxy group amount of (A) and (B) minus the phenolic OH group amount of (C). An epoxy resin composition, characterized in that it is in an amount corresponding to NH groups with a stoichiometry of 5 to 1.0. (A) Bifunctional epoxy resin (B) Trifunctional epoxy resin (C) Phenolic compound represented by the following formula (However, X1 to X8 represent Br, Cl, and H, of which 4
Above Br or Cl, R1, R2 represent each H or CH ₃₎ (D) dicyandiamide, 2,6-carboxymethyl Leni ruby guar acetonide, O- tolylbiguanide, diphenylguanidine, mackerel pills dihydrazide, azelate Lyle dihydrazide, isophthalic acid At least one selected from the group consisting of dihydrazides.