JPH0471928B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an epoxy resin composition for composite materials in which a specific polyglycidyl derivative and an epoxy curing agent are combined. [Prior Art] Fiber-reinforced composite materials reinforced with fibers such as carbon fibers, alumina fibers, and fully aromatic polyamide fibers have excellent mechanical performance, so they are used for structural parts, etc. in various industries. Furthermore, it is used in sports and leisure products. Various matrix resins are used, but they have excellent mechanical properties, no volatile matter during curing, small shrinkage during curing, and excellent adhesion to carbon fibers. For this reason, epoxy resins have been widely used (for example, Japanese Patent Publication No. 58-40975
(Refer to Japanese Patent Application Laid-Open No. 62-57416). In all of these, the unidirectional laminated materials had a 0° direction bending strength (converted to a fiber volume content of 60%) of about 190 Kg/mm ² , and an interlaminar shear strength of about 10 Kg/mm ² . In response to these current conditions, various improvements have been made aimed at improving mechanical properties and further improving heat resistance. Japanese Patent Publication No. 62-15570 discloses N,N-diglycidylaminophenyl glycidyl ether and/or N,N- as a composition with high interlayer shear strength.
An epoxy resin composition whose main components are an epoxy resin consisting of diglycidylaniline and diaminodiphenylsulfone is mentioned. This composition has a maximum interlaminar shear strength of 12.8 Kg/ ^mm2 , but 0°
The maximum directional bending strength was 192 Kg/mm ² .
Moreover, the curing temperature was high at 170°C, and it was necessary to post-process at a high temperature of 190°C, so it lacked versatility. Also, in Japanese Patent Application Laid-open No. 183340-183342,
As a composition that improves mechanical properties and heat resistance,
A polyglycidyl derivative of 4-amino-m-cresol and/or 4-amino-o-cresol;
Composition consisting of diaminodiphenyl sulfone and/or diaminodiphenylmethane (), N, N,
N′,N′-tetraglycidyl (aminophenyl)
Methane and/or its condensation products, 4-amino-
A composition () consisting of a polyglycidyl derivative of m-cresol and/or 4-amino-o-cresol compound and/or a condensate thereof, and diaminodiphenylsulfone and/or diaminodiphenylmethane; Lac type epoxy resin, cresol novolac type epoxy resin and/or bisphenol A diglycidyl ether type epoxy resin, polyglycidyl derivative of 4-amino-m-cresol and/or 4-amino-o-cresol compound and/or its Three types of compositions () are mentioned: a condensate and a dicyandiamide or acid hydrazide compound.
Bending strength in 0° direction 215Kg/mm ² , interlaminar shear strength 13.6
Kg/mm ² has been achieved with the composition (), but it requires high temperature and long time for curing at 150℃ for 1 hour and post-curing at 180℃ for 4 hours, and the curing conditions are 120℃ for 1 hour and post-curing for 1 hour.
In the composition () at 130°C for 2 hours, 0°
Directional bending strength 210Kg/mm ² , interlaminar shear strength 11.2Kg/
mm ² , which is a rather low value. [Problems to be solved by the invention] As mentioned above, 4-amino-
Even if polyglycidyl derivatives of m-cresol and/or 4-amino-o-cresol are used, when diaminodiphenylsulfone is used as a curing agent, curing occurs at a high temperature of 150°C or higher, and post-curing occurs at a high temperature of 180°C. Otherwise, the composite material will not have sufficient physical properties and will lack versatility. Furthermore, when dicyandiamide is used as a curing agent, it can be cured at a low temperature of 120 to 130°C, but the 0° bending strength and interlaminar shear strength of the composite material using the resulting resin composition will be low. In view of the above-mentioned current situation, the present inventors investigated and found that by combining a specific epoxy compound, curing agent, and curing accelerator, it can be cured at a temperature of 150°C or less, and has a bending strength of 220 kg/cm in the 0° direction.
The present invention was completed based on the discovery that it is possible to obtain an epoxy resin composition for composite materials that has an interlaminar shear strength of 2 mm ² or more and a significantly higher interlaminar shear strength than conventional ones. [Means for Solving the Problems] The present invention provides: (A) an epoxy compound containing 10 to 100% by weight of m- or o-methyl-p-N,N-diglycidylaminophenyl glycidyl ether or an oligomer thereof; , (B) 50 to 200% of the equivalent weight relative to the epoxy compound
of diaminodiphenyl sulfone and/or diaminodiphenylmethane, (C) 1 to 10 parts per 100 parts by weight of the epoxy compound
Parts by weight of at least one compound selected from the group consisting of dicyandiamide, 2,6-xylenyl biguanide, o-tolyl biguanide, diphenylguanidine, adipyl dihydrazide, azelyl dihydrazide, isophthalic acid dihydrazide, (D) 1.5 to 15 per 100 parts by weight of epoxy compound
General formula for parts by weight (In the formula, X ₁ and X ₂ may be the same or different,
Chlorine atom, bromine atom, nitro group, methyl group, hydrogen atom, methoxy group, ethoxy group or group

This is an epoxy resin composition for composite materials containing a urea compound represented by the formula: CH ₃ ) ₂ . The resin composition of the present invention has the general formula (In the formula, X is a hydrogen atom, a chlorine atom, a bromine atom, or a hydroxyl group, and R is a hydrogen atom, a group

[Formula] or

〔Effect of the invention〕

The carbon fiber composite material using the epoxy resin composition of the present invention as a matrix resin has a bending strength in the 0° direction of
It has physical properties of 220Kg/mm ² or more, interlaminar shear strength 10Kg/mm ² or more, and can be cured at low temperatures of 150°C or less. Therefore, it can be expected to have a wide range of applications, from sports and leisure fields such as fishing rods and golf shafts to industrial fields such as automobiles, aircraft, and rockets. Reference example 1 m-methyl-p-N,N-diglycidylaminophenyl glycidyl ether [epoxy compound
(a)] synthesis m-methyl-p-aminophenol 54.6g
(0.444 mol), 370 g (4 mol) of epichlorohydrin, 84 g of 95% ethyl alcohol, 0.65 g of lithium hydroxide hydrate, and 6 ml of water (3.7 mol % based on phenolic hydroxyl groups) were stirred at room temperature ( The reaction was carried out at 25°C for 137 hours. This mixture was heated to 55-60°C, and 66.5 g (1.66 mol) of 50% by weight aqueous sodium hydroxide was added and heated for 3 hours. Reduce pressure (30mmHg) until the temperature of the residue is 65℃
Distillation was performed to remove water, alcohol and excess epictorhydrin. The residue was dissolved in benzene and washed repeatedly with water to remove salts and excess sodium hydroxide. The washed benzene solution was distilled under reduced pressure (30 mmHg) to remove benzene.
The epoxy equivalent of the obtained dark brown liquid epoxy compound (a) was 105 g/eq. Reference example 2 o-methyl-p-N,N-diglycidylaminophenyl glycidyl ether [epoxy compound
(b)] synthesis Epoxy compound (b) was obtained in the same manner as in Reference Example 1 except that o-methyl-p-aminophenol was used as the starting material. Obtained epoxy compound (b)
The epoxy equivalent was 104 g/eq. Reference example 3 N-[4-(2-hydroxy-3-phenoxypropoxy)-phenyl]-acetamide [(E)-1] Mix p-hydroxyacetanilide and phenyl glycidyl ether at a ratio of 1:1.05 (mole ratio),
When the reaction was carried out by heating at 160°C for 60 minutes, a viscous liquid reaction product was obtained at room temperature. This was heated to 150° C. under a reduced pressure of 1 mmHg to remove unreacted phenyl glycidyl ether to obtain reaction product (E)-1.
The infrared absorption spectrum of reaction product (E)-1 was measured, and it was confirmed that there was no epoxy group. Also, reactant (E)−
When GPC (gel permeation chromatography) was measured using a chloroform solution of 1, reactant (E)-1 was found to contain, in addition to the 1:1 reactant,
The reaction mixture contained a highly reacted polymer compound. Reference example 4 N-phenyl-N-(2-hydroxy-3-phenoxypropyl)-acetoacetamide [(E)-
2] Acetoacetanilide and phenyl glycidyl ether were prepared in the same manner as in Reference Example 3 to 1:1.2 (molar ratio).
was heated at 170°C for 1 hour to react, and the reaction product (E)-
I got 2. This (E)-2 is 1:1 as in Reference Example 3.
The reaction mixture contained, in addition to the above reactants, a polymer compound that had undergone further reaction. Reference example 5 N-(2-hydroxy-2-cyclohexene oxide ethyl)-aniline [(E)-3] Aniline and vinylcyclohexene were mixed at 100°C in the same manner as in Reference Example 3 at a molar ratio of 1:2.1.
After heating for 45 minutes to react, a viscous liquid reactant (E)
I got -3. This (E)-3 is similar to Reference Example 3, 1:
The reaction mixture contained a polymer compound in which the reaction had further progressed in addition to the first reactant. Examples 1 to 16 and Comparative Examples 1 to 15 A unidirectional carbon fiber composite material was molded using the resin composition shown in Table 1 as a matrix resin, and the 0° direction bending strength and interlaminar shear strength of the resulting molded pair were measured. did. The results are also shown in the table. The molded bodies in the table were created by the following method. Epoxy resin, curing agent and reactant (E) in the proportions shown in the table,
Mix uniformly at a temperature of 60 to 70°C to obtain a resin composition for matrix. This resin composition is heated to form a thin film on release paper to create a so-called hot melt film, and this film is wound around a drum, and carbon fiber (Pyrofil T-1, manufactured by Mitsubishi Rayon Co., Ltd.) is heated and impregnated. prepreg was created. The obtained prepregs are laminated and adjusted so that the carbon fiber content after molding is 60 Vol%, and then placed in a mold and cured by heating for a certain period of time in a heat press heated to a predetermined temperature to form a molded body. Created. The method for measuring the physical properties of the carbon fiber composite materials in the table is as follows. (1) Interlaminar shear strength Using a plate-shaped specimen with a length of 15 mm, width of 10 mm, and thickness of 2 mm, a fulcrum with a span interval of 8 mm (tip radius of 3.2 mm)
A three-point bending test was performed by pressing the center of the sample with an indenter with a tip radius of 3.2 mm, and the crosshead speed was 2 mm/min. The interlaminar shear strength was calculated using the following formula. The span interval is L (mm), the sample thickness is T (mm), the sample width is W (mm), and the breaking load is P.
(Kg). Interlaminar shear strength = 3P/4WT (Kg/mm ² ) (2) Bending strength Using a plate specimen with a length of 100 mm, a width of 10 mm, and a thickness of 2 mm, the span spacing was 80 mm, and the other conditions were the same as for the interlaminar shear strength. 0° by the following formula.
The directional bending strength was calculated. Bending speed = 3PL/2WT ² (Kg/mm ² ) The symbols in the table indicate the following compounds. Ep.154: Phenolborak type epoxy resin (manufactured by Schiel Chemical Co., Ltd.) ELM-120: m-N,N-diglycidylaminophenyl glycidyl ether (manufactured by Sumitomo Chemical Co., Ltd.) MY-720: Diaminodiphenylmethane tetraglycidylamine (manufactured by Ciba Geigy) Ep.828: Bisphenol A epoxy resin (manufactured by Schiel Chemical) DADPS: Diaminodiphenylsulfone DICY: Dicyandiamide DCMU: 3-(3,4-dichlorophenyl)
-1,1-dimethylurea The amount of reactant (E) added indicates the weight % based on the total amount of components (A) to (D). As a result, when the resin composition of the present invention is used as a matrix resin, the bending strength in the 0° direction of carbon fiber composite materials is 220 Kg/mm ² or more, and the interlaminar shear strength is 10
It can be seen that Kg/mm ² can be easily achieved. On the other hand, in Comparative Examples, the physical properties of the cured products were poor at temperatures below 150°C, and some resin compositions were insufficiently cured, making it difficult to measure the physical properties. In particular, when diaminodiphenylsulfone or dicyandiamide shown in Comparative Examples 9 to 15 is used alone, curing is insufficient, and even if cured, the bending strength and interlaminar shear strength of the carbon fiber composite material are low. It can be seen that the combination of diaminodiphenylsulfone and dicyandiamide cures at low temperatures and in a short time, and also increases the bending strength and interlaminar shear strength of the resulting carbon fiber composite material.

【table】

[Table] Examples 17 to 27 and Comparative Examples 16 and 17 As epoxy compounds, epoxy compound (a)/
Ep.154 = 40/60 (weight%) composition, 4,
4'-Diaminodiphenyl sulfone and reactant (E)-
Epoxy resin compositions were prepared by changing the amount of 1 added, and otherwise heated at 130° C. for 1 hour in the same manner as in Examples 1 to 16 to obtain carbon fiber composite materials. Tables 2 and 3 show the measurement results of the 0° direction bending strength and interlaminar shear strength of the molded product.

【table】

[Table] Example 28 and Comparative Example 18 Carbon fiber composite materials obtained using reaction product (E)-3 were immersed in hot water at 50°C for 24 hours, and the bending strength in the 0° direction and interlaminar shear were measured before and after moisture absorption. Table 4 shows the results of measuring the strength. It is clear that the carbon fiber composite material using the resin composition of the present invention has a low amount of water absorption, and therefore the deterioration of physical properties due to moisture absorption is small.

[Table] Examples 29 to 32 0.1 part by weight of trimethylamine was added to 100 parts by weight of the epoxy compound (1) shown in Reference Example 1,
A viscous resin was obtained by heating at 100°C for 30 minutes. The epoxy equivalent of the obtained epoxy resin is 196,
An oligomer with some of the epoxy groups reacted was obtained. Using this oligomer, unidirectional carbon fiber composite materials were molded in the same manner as in Examples 1 to 16.
Table 5 shows the matrix resin composition used, the 0° direction bending strength, and the interlaminar shear strength of the molded product.

[Table] Examples 33 to 48 Epoxy resins using epoxy compound (1) as the epoxy resin and (E)-1 as the reactant E, with varying proportions of components (B), (C), and (D) A carbon fiber composite material was obtained as a matrix resin in the same manner as in Examples 1 to 16. Table 6 shows the composition of the matrix resin used and the measurement results of 0° direction bending strength and interlaminar shear strength.

[Table] *3 Indicates the weight percent added to the mixture of epoxy compound (a), components (B), (C) and (D).

Claims (1)

[Claims] 1 (A) an epoxy compound containing 10 to 100% by weight of m- or o-methyl-p-N,N-diglycidylaminophenyl glycidyl ether or an oligomer thereof; (B) an epoxy compound containing 10 to 100% by weight of m- or o-methyl-p-N,N-diglycidylaminophenyl glycidyl ether; vs. 50-200% of equivalent weight
of diaminodiphenyl sulfone and/or diaminodiphenylmethane, (C) 1 to 10 parts per 100 parts by weight of the epoxy compound
Parts by weight of at least one compound selected from the group consisting of dicyandiamide, 2,6-xylenyl biguanide, o-tolyl biguanide, diphenylguanidine, adipyl dihydrazide, azelyl dihydrazide, isophthalic acid dihydrazide, (D) 1.5 to 15 per 100 parts by weight of epoxy compound
General formula for parts by weight (In the formula, X ₁ and X ₂ may be the same or different,
An epoxy resin composition for composite materials containing a urea compound represented by a chlorine atom, a bromine atom, a nitro group, a methyl group, a hydrogen atom, a methoxy group, an ethoxy group, or a group (representing the formula). 2 (A) component m- or o-methyl-p-N,
The epoxy compound used in combination with N-diglycidylaminophenyl glycidyl ether or its oligomer is a phenol novolak type epoxy resin and/or
The epoxy resin composition for composite materials according to claim 1, which is a cresol novolak type epoxy resin. 3. The epoxy resin composition for composite materials according to claim 1, wherein the component (C) is dicyandiamide. 4 Component (D) is 3-(3,4-dichlorophenyl)-
The epoxy resin composition for composite materials according to claim 1, which is 1,1-dimethylurea. 5 General formula (In the formula, or Contains a reaction product obtained by reacting with an epoxy compound represented by (wherein X has the above meaning) in an amount of 100% by weight or less based on the total amount of components (A) to (D). The first, characterized by
The epoxy resin composition for composite materials according to the claims. 6. The epoxy resin composition for composite materials according to claim 5, which contains p-hydroxyacetanilide or a reaction product of acetoacetanilide and phenyl glycidyl ether. 7. The epoxy resin composition for composite materials according to claim 5, which contains a reaction product of aniline and 4-vinylcyclohexene dioxide (4).