JP4956013B2 - Composite intermediate - Google Patents

Description

  The present invention relates to an intermediate for composite materials used in aircraft, automobiles, general industries, and the like.

  As matrix resin for composite materials, epoxy resin has been widely used because of its adhesiveness and high rigidity. However, as the required performance for composite materials has become more sophisticated, various studies have been made on the matrix resin used. Has been made. Examples of the required performance for the composite material include heat resistance, impact resistance (toughness), and high mechanical characteristics (compression characteristics) in a high temperature and high humidity environment.

  For example, for applications requiring heat resistance, conventionally, N, N, N ′, N′-tetraglycidylmethane (TGDDM) is the main component and 4,4′-diaminodiphenylmethane (DDS) is the curing agent. Epoxy resin compositions have been widely used. However, this composition is excellent in heat resistance and rigidity, but has low impact resistance. Therefore, bifunctional epoxy resin represented by bisphenol A type epoxy resin may be used as the main component to give impact resistance, but in that case the heat resistance is lowered and the required performance is satisfied. Often not. Thus, it has been very difficult to achieve both impact resistance and heat resistance.

  In addition, as disclosed in Patent Documents 1 and 2, for example, a thermoplastic resin typified by polyethersulfone (PES) is added to impart impact resistance to a highly heat-resistant epoxy resin composition. There is a way to do it. However, in order to obtain a certain effect by this method, since it is necessary to increase the amount of addition, not only the characteristics strongly required for the composite material intermediate such as moderate tack and flexibility are significantly reduced, As the viscosity of the matrix resin increases, there is also a problem that the processability of the composite material intermediate significantly decreases.

Therefore, in the case of Patent Document 3, the present applicant maintains characteristics such as appropriate tack and flexibility required for the composite material intermediate and good processability, and further has heat resistance, impact resistance, high temperature and high humidity. As a composite material intermediate that has mechanical properties in the environment, a resin composition in which a tetrafunctional epoxy resin and an aromatic amine are mixed with a reaction product of a bifunctional epoxy resin, a trifunctional epoxy resin, or a phenol compound is a matrix resin The technology to be used as is proposed.
JP 58-124126 A JP-A-62-153349 Japanese Patent No. 3026372

However, recently, the required performance of the market for composite materials has been increasing, and materials having higher heat resistance, impact resistance, and mechanical properties in a high temperature and high humidity environment have been demanded.
Patent Document 3 describes that higher impact resistance can be expressed by further blending the above resin composition with an elastomer such as a butadiene-acrylonitrile copolymer having carboxyl groups at both ends. However, when a rubber component such as an elastomer is simply blended, the impact resistance is improved according to the blending amount, but the heat resistance is still lowered. In addition, when the amount of the rubber component is increased, there is a problem that the dispersibility and compatibility of the rubber component are deteriorated. With such a technology, the required performance in the market cannot be sufficiently realized.

  The present invention has been made in view of the above circumstances, and it is an object to provide a composite material intermediate that can provide a composite material that satisfies high heat resistance, impact resistance, and mechanical properties in a high temperature and high humidity environment. To do.

（式中Ｘは水素原子、炭素数が６以下のアルキル基、Ｂｒからなる群より選ばれる１種を示し、Ｙは直接結合、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−ＳＯ_２−、

からなる群より選ばれる１種を示す。） As a result of intensive studies, the present inventors have formulated a resin composition in which, in addition to a bifunctional epoxy resin, a trifunctional epoxy resin, and a specific phenol compound, an oligomer in which a specific rubber component is reacted in a specific ratio is mixed with other specific components. When the product is used as a matrix resin, it has been found that the above problems can be solved, and the present invention has been completed.
The composite material intermediate of the present invention is a composite material intermediate in which a reinforcing fiber is impregnated with a resin composition, and the resin composition contains 20 to 60 mol% of a bifunctional epoxy resin (a1) and 20 to 20 mol%. A resin component comprising a total of 100 mol% of 50 mol% of a trifunctional epoxy resin (a2) and 20 to 50 mol% of a phenol compound (a3) represented by the general formula (I) can react with an epoxy group. It is obtained by reaction with a rubber component (a4) having a functional group, has substantially no phenolic hydroxyl group, and the amount of the rubber component (a4) relative to 100 parts by mass of the resin component is 1 to 25 parts by mass. An oligomer (A),
A bifunctional epoxy resin (B);
A tetrafunctional epoxy resin (C);
An aromatic amine compound (D),
When the resin component in the oligomer (A) is 15 to 60 parts by mass, the bifunctional epoxy resin (B) is 10 to 40 parts by mass, and the tetrafunctional epoxy resin (C) is 15 to 75 parts by mass. The aromatic amine compound (D) is included in a range where the theoretical equivalent to the epoxy group is 90 to 175%.

(In the formula, X represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or one selected from the group consisting of Br, and Y represents a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —SO. _2-

1 type selected from the group consisting of )

  ADVANTAGE OF THE INVENTION According to this invention, the composite material intermediate body which can provide the composite material which satisfy | fills the high heat resistance, impact resistance, and the mechanical characteristic in a high temperature high humidity environment can be provided.

Hereinafter, the present invention will be described in detail.
The composite material intermediate of the present invention is obtained by impregnating reinforcing fibers with a resin composition containing components (A) to (D) described below as essential components.
[(A) component]
The component (A) has a bifunctional epoxy resin (a1), a trifunctional epoxy resin (a2), a phenol compound (a3) represented by the general formula (I), and a functional group capable of reacting with an epoxy group. It is an oligomer reacted with the rubber component (a4).
The bifunctional epoxy resin (a1) component is an epoxy resin having two epoxy groups in the molecule, and is a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a brominated epoxy resin thereof, or a bisphenol S type. Typical examples include epoxy resins, epoxy resins having an alkyl skeleton as the main chain, biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, fluorene type epoxy resins, and epoxy resins modified by these. These may be used alone or in combination of two or more. Among these, for example, a bisphenol type epoxy resin is represented by the following general formula (II).

  The (a2) component trifunctional epoxy resin is an epoxy resin having three epoxy groups in the molecule, and typical examples thereof include N, N, O-triglycidyl-P- or -m-amino. Examples include phenol, N, N, O-triglycidyl-4-amino-m- or -5-amino-o-cresol, 1,1,1- (triglycidyloxyphenyl) methane, and the like. In addition, as the trifunctional epoxy resin, a commercially available trifunctional epoxy resin can also be used. For example, Ep630 and YX-4 manufactured by Japan Epoxy Resin, MY0510 manufactured by Huntsman, Examples thereof include ELM-100 manufactured by Sumitomo Chemical Co., Ltd., EXA4506 manufactured by Dainippon Ink and the like. These trifunctional epoxy resins may be used alone or in combination of two or more.

  The phenol compound as the component (a3) satisfies the structural formula (I) above. Specifically, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxy-3,3 ′, 5, 5′-tetramethyldihydroxybiphenyl, 4,4′-dihydroxy-3,3 ′, 5,5′-tetra-tert-butylbiphenyl, bisphenol F, tetramethylbisphenol F, bisphenol A, tetramethylbisphenol A, bisphenol S, Examples include tetramethylbisphenol S and 4,4 ′-(p-phenylenediisopropylidene) bis (xylenol). These may be used alone or in combination of two or more.

  The rubber component having a functional group capable of reacting with the epoxy group as the component (a4) is a rubber component having a terminal group such as a hydroxyl group, a carboxyl group, an amino group, and an amide group that can react with the epoxy group. Butadiene / acrylonitrile copolymer, butadiene rubber, acrylic rubber, styrene / butadiene elastomer and the like. Among these, it is preferable to use acrylic rubber having a crosslinked skeleton in the inside as the component (a4) because both the heat resistance and impact resistance can be imparted to the finally obtained composite material.

The rubber component (a4) has a multilayer structure such as a core-shell structure as long as it has a functional group capable of reacting with an epoxy group at a site in contact with the bifunctional epoxy resin (a1) or the trifunctional epoxy resin (a2). Even the rubber component can be suitably used. In the case of the rubber component (a4) having a core-shell structure, a rubber component having a lower elastic modulus at a portion forming the core than that at a portion forming the shell can be used more suitably.
An example of such a rubber component is metablene manufactured by Mitsubishi Rayon Co., Ltd.

The oligomer (A) is obtained by reacting the component (a1), the component (a2), the component (a3), and the component (a4) described above with heating and optionally in the presence of a catalyst. It is done.
In this reaction, it is necessary that at least 70% or more of the phenol compound as the component (a3) is reacted in the obtained oligomer (A).
Here, when the phenol compound exceeding 30% remains unreacted, the water resistance and storage stability of the obtained resin composition are significantly lowered. Preferably, the reaction rate of the phenol compound is 90% or more. In addition, it can be analyzed by GPC how much a phenolic compound remains.

  Specific reaction conditions for preparing the oligomer (A) may be appropriately set such that the reaction proceeds relatively gently and 70% or more of the phenolic hydroxyl groups react as described above. When the catalyst is not used, it is usually suitable at 100 to 150 ° C. for 5 to 24 hours, and when the catalyst is used, it is usually suitable at 100 to 130 ° C. for 2 to 6 hours. The catalyst can be used without particular limitation as long as it moderately accelerates the reaction between the epoxy group and the phenol compound, but triphenylphosphine is particularly preferable. What is necessary is just to set the quantity of a catalyst suitably so that reaction may advance smoothly.

The oligomer (A) is prepared by first reacting the bifunctional epoxy resin of component (a1) and / or the trifunctional epoxy resin of component (a2) with the rubber component of component (a4). You may carry out in two steps which add and react an essential component.
At that time, the first-stage reaction in which the component (a1) and / or the component (a2) and the component (a4) are reacted may be carried out at a temperature of 100 to 180 ° C. by adding a catalyst as necessary.
Furthermore, instead of carrying out the first-stage reaction, a rubber-modified epoxy resin comprising a component (a1) and / or a component (a2) and a component (a4) and available as a commercial product may be used.
Available rubber-modified epoxy resins include Epicron TSR-601, TSR-960, TSR-930, Dainippon Ink & Chemicals, Inc., where the epoxy resin is a bifunctional epoxy resin, and ACI Japan Limited. EPI-REZ 58005, 58006, Epicote YL6308, YL6347 of Yuka Shell Epoxy Co., Ltd. Epoxy BPA328, BPF307, CX-MN201, CX-MN133, etc. made by Nippon Shokubai Co., Ltd., Toto Kasei Epoto YR- 628, YR-692, YR-693, etc., a crosslinked rubber-modified epoxy resin of Nippon Synthetic Rubber Co., Ltd.).

Among these rubber-modified epoxy resins, acrylic rubber is preferably used as the rubber component (a4). Epoxy BPA328, BPF307, CX-MN201, CX are epoxy resins made by Nippon Shokubai. -Tonsei Kasei Epototo YR-628, YR-692, YR-693, such as MN133.
As the acrylic rubber-modified epoxy resin, a resin in which a fine powdery acrylic rubber having a particle size of 40 μm or less is dispersed in the epoxy resin is suitably used in addition to the epoxy resin modified with an acrylic rubber. One type or two or more types of acrylic rubber may be included.

  The oligomer (A) can be prepared as described above, and the ratio of each component at that time is 20 to 60 mol% of the bifunctional epoxy resin (a1) and 20 to 50 mol% of the trifunctional epoxy resin (a2). ) And 20 to 50 mol% of the phenolic compound (a3) in a total amount of 100 mol%, the rubber component (a4) needs to be in a range of 1 to 25 mass parts.

  Here, if the ratio of the bifunctional epoxy resin (a1) is less than 20 mol%, the impact resistance of the resin composition is insufficient, and if it exceeds 60 mol%, the heat resistance of the resin composition is lowered. If the ratio of the trifunctional epoxy resin (a2) is less than 20 mol%, sufficient heat resistance cannot be obtained, and if it exceeds 50 mol%, gelation may occur during the preparation of the oligomer (A). If the ratio of the phenolic compound (a3) is less than 20 mol%, sufficient impact resistance cannot be obtained, and if it exceeds 50 mol%, not only the gelation may occur during the preparation of the oligomer (A), but 20 % Or more of the phenolic hydroxyl group remains unreacted. Moreover, the impact resistance of a resin composition falls that the ratio of a rubber component (a4) is less than 1 mass part with respect to 100 mass parts of resin components which consist of (a1)-(a3) component, and 25 masses. When it exceeds the part, the heat resistance of the resin composition is lowered, the viscosity of the resin composition becomes very high, and handling becomes difficult. A more preferable ratio of the rubber component (a4) is 3 to 20 parts by mass.

In the oligomer (A) thus obtained, the phenolic compound (a3) and the rubber component (a4) are each in an island phase, and the bifunctional epoxy resin (a1) and the trifunctional epoxy resin (a2) are in a sea phase. A certain sea-island structure is formed. Therefore, in the resin composition containing such an oligomer (A), a decrease in heat resistance that is recognized when a rubber component is simply blended is suppressed, and high heat resistance can be maintained.
In such an oligomer (A), the sea phase functions as a hard segment and the island phase functions as a soft segment. In particular, the soft segment includes an island phase composed of a phenolic compound (a3) and a rubber component ( It is comprised by the island phase which consists of a4). Therefore, the synergistic effect of each soft segment is expressed, and compared with the case where the soft segment is composed of only one of them, the impact resistance of the resulting resin composition is greatly improved. A composite material that exhibits post-compression strength can be provided.
Furthermore, in such an oligomer (A), since the rubber component (a4) is incorporated as a soft segment in the skeleton of the oligomer (A), the resulting resin composition has reduced moisture absorption. As a result, it is possible to provide a composite material in which deterioration of mechanical properties due to moisture absorption in a high temperature and high humidity environment is suppressed.
Specifically, by using such an oligomer (A) together with components (B) to (D) described later, the resulting resin composition has high heat resistance with a glass transition temperature (Tg) exceeding 160 ° C. To express. And the composite material using this resin composition has compressive strength after impact exceeding 323 MPa, and compressive strength after moisture absorption at 93 ° C. exceeds 1100 MPa. Therefore, by using a resin composition in which such an oligomer (A) and components (B) to (D) described later are blended, high heat resistance, impact resistance, high temperature and high humidity, which have been difficult in the past, have been difficult. It becomes possible to provide a composite material that satisfies all the mechanical properties in the environment.

[Component (B)]
As the bifunctional epoxy resin used as the component (B), various epoxy resins exemplified above as the component (a1) can be similarly used. In addition, the bifunctional epoxy resin used for the component (a1) and the component (B) may be the same or different.

[Component (C)]
(C) component improves the heat resistance of a resin composition more, Comprising: As a tetrafunctional epoxy resin used, N, N, N ', N'-tetraglycidylamino diphenylmethane, N, N, Representative examples thereof include N ′, N′-tetraglycidyl 4,4 ′-(4-aminophenyl) -p-diisopropylbenzene, 1,1,2,2- (tetraglycidyloxyphenyl) ethane and the like. .

[(D) component]
Component (D) acts as a curing agent, and examples of the aromatic amine compound used include 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, and 4,4′-diamino. Aromatic amines such as diphenylmethane, 4,4′-diaminodiphenyl ether, trimethylene-bis (4-aminobenzoate) are used. Among these, 4,4′-diaminodiphenyl sulfone and 3,3′-diaminodiphenyl sulfone are particularly preferable from the viewpoints of heat resistance expression and availability.

[Resin composition]
In the present invention, the resin composition impregnated in the reinforcing fiber is 10 to 40 parts by mass of the component (B) and 15 to 15 parts of the component (C) with respect to 15 to 60 parts by mass of the resin component in the component (A). It can be produced by blending 75 parts by mass and further the aromatic amine compound (D) in a range where the theoretical equivalent to the epoxy group calculated from the following formula (III) is 90 to 175% equivalent. When the ratio of the components (A) to (C) is out of these ranges, a composite material that satisfies all the characteristics of high heat resistance, impact resistance, and mechanical characteristics under a high temperature and high humidity environment cannot be provided. Further, when the ratio of the component (D) is less than 90% equivalent, the resin composition is insufficiently cured and satisfactory physical properties cannot be obtained. Conversely, when the ratio exceeds 175% equivalent, the crosslinking density is greatly increased. The heat resistance and solvent resistance are greatly reduced. More preferably, the component (B) is 20 to 35 parts by mass and the component (C) is 20 to 60 parts by mass with respect to 20 to 50 parts by mass of the resin component in the component (A). Moreover, about (D) component, 100-150% equivalent of a theoretical equivalent is more preferable.

Other epoxy resins (E) can be used in combination with the resin composition within a range that does not impair the overall physical property balance. Examples of other epoxy resins include novolac type epoxy resins.
For example, as other epoxy resins, epoxy resins having precursors such as triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, triglycidylaminocresol and various isomers, novolac type epoxy resins, etc. Examples of the epoxy resin having a carbon-carbon double bond as a precursor include, but are not limited to, alicyclic epoxy resins and the like, and epoxy resins having a polygonal skeleton such as naphthalene. Furthermore, the epoxy resin which modified a part of epoxy group with a thermoplastic resin, an elastomer, isocyanate, etc. can be illustrated. Moreover, although the brominated epoxy resin which brominated these epoxy resins can also be used preferably, it is not limited to these.
The amount of component (E) used is preferably 20% or less of the total resin component, which is the sum of components (A), (B) and (C).

  Further, the resin composition includes so-called elastomer components such as a butadiene-acrylonitrile copolymer having carboxyl groups at both ends, and thermoplastic resin components such as polyethersulfone, polysulfone, polyetheretherketone, polyetherimide, and polyvinylbutyrate. You can also use it depending on the purpose. What is necessary is just to set the usage-amount of these components suitably according to the objective within the range which does not destroy the whole physical property balance. Further, an inorganic compound such as silica powder, aerosil, microballoon, antimony trioxide, etc. may be blended depending on the purpose.

[Reinforcing fibers and composite intermediate materials]
Examples of reinforcing fibers impregnated with such a resin composition include carbon fibers, glass fibers, aramid fibers, boron fibers, silicon carbide fibers, and the like, and these include milled fibers, chopped fibers, continuous fibers, and various fabrics. Etc. can be used. Among these, carbon fibers having a tensile strength of 450 MPa or more and a tensile elongation of 1.7% or more and having high strength and high elongation in the form of continuous fibers or various woven fabrics are most preferably used.
The method for impregnating the reinforcing fiber with the resin composition is not particularly limited, and may be a normal method.
According to the composite intermediate material obtained by impregnating the above-mentioned resin composition into the reinforcing fiber, the composite satisfying all of the high heat resistance, impact resistance, and mechanical properties under the high temperature and high humidity environment, which has been difficult in the past. Material can be given.

Hereinafter, the present invention will be described specifically by way of examples.
In addition, it shows below about each used component. Moreover, the average molecular weight of the epoxy resin used for calculation of molar ratio was computed from following Formula. However, the epoxy resin having a rubber component was calculated by a value excluding the rubber component.
Average molecular weight = (epoxy equivalent) × (average number of functional groups per molecule)

Component (a1) and Component (B) Epicote 807: manufactured by Japan Epoxy Resin, bisphenol F type epoxy resin, average molecular weight: about 312
Epicoat 828: manufactured by Japan Epoxy Resin Co., Ltd., bisphenol A type epoxy resin, average molecular weight: about 340
Reaction product of component (a1) and component (a4) (epoxy resin having a rubber component)
BPF307: manufactured by Nippon Shokubai Co., Ltd., crosslinked acrylic rubber-modified bisphenol F type epoxy resin, average molecular weight 312 and acrylic rubber content 20% by mass
BPA 328: manufactured by Nippon Shokubai Co., Ltd., crosslinked acrylic rubber-modified bisphenol A type epoxy resin, average molecular weight 340, acrylic rubber content 20% by mass
Component (a2) ELM-100: manufactured by Sumitomo Chemical Co., ELM-100, average molecular weight 318
Ep630: manufactured by Japan Epoxy Resin Co., Ltd., average molecular weight 318
Component (a3) Tetramethylbisphenol A (molecular weight 284)
・ 4,4'-dihydroxybiphenyl (Honshu Chemical Co., Ltd., molecular weight 186)
4,4 ′-(p-phenylenediisopropylidene) bis (2,6-xylenol) (molecular weight 402)
(A4) Component As a rubber component having a multilayer structure of two or more phases,
WAK104: Mitsubishi Rayon-made Metablen epoxy equivalent 32600 (g / eq)
WAK105: Mitsubishi Rayon-made Metablen epoxy equivalent 34500 (g / eq)
(C) component-Epicoat 604: Japan epoxy resin company make, TGDDM, average molecular weight 302
Component (D) DDS: 4,4′-diaminodiphenyl sulfone (Seika Cure S Wakayama Seika Co., Ltd.)

    The amount of the unreacted phenol compound (a3) contained in the oligomer A component was measured by GPC. For measurement of GPC, Tosoh: HLC-8220GPC was used. After 0.2 wt% of the oligomer was dissolved in THF as the eluent, a TSK-GEL column was used, and the flow rate was 1.0 ml / min. Measured. The peak area of the phenol compound before the reaction was taken as 1, and the amount of the phenol compound after the reaction was quantified.

[Preparation Example 1]
A reaction vessel containing BPF307: 850 g which is a reaction product of component (a1) and component (a4), ELM-100: 477 g which is component (a2), and 426 g of tetramethylbisphenol A which is component (a3). And reacted at 120 ° C. for 8 hours to obtain an oligomer (1). Tetramethylbisphenol A present in the oligomer was 10% or less when the amount of the phenol compound before the reaction was 100%.
Moreover, the mass part of the rubber component (a4) when the total of the components (a1) to (a3) was 100 parts by mass was 10.7 parts by mass.

[Preparation Example 2]
An oligomer (2) was obtained in the same manner as in Preparation Example 1, except that 426 g of tetramethylbisphenol A was changed to 279 g of the above 4,4′-dihydroxybiphenyl and the reaction conditions were changed to 110 ° C. for 6 hours. The 4,4′-dihydroxybiphenyl present in the oligomer was 10% or less when the amount of the phenol compound before the reaction was 100%.
Moreover, the mass part of the rubber component (a4) when the total of the components (a1) to (a3) was 100 parts by mass was 12.5 parts by mass.

[Preparation Example 3]
Tetramethylbisphenol A: 426 g was changed to the above 4,4 ′-(p-phenylenediisopropylidene) bis (2,6-xylenol): 603 g, and 12 g of triphenylphosphine was added as a catalyst. An oligomer (3) was obtained in the same manner as in Preparation Example 1, except that the reaction was performed for a period of time. The unreacted phenol compound present in the oligomer was 10% or less when the amount of the phenol compound before the reaction was 100%.
Moreover, the mass part of the rubber component (a4) when the total of the components (a1) to (a3) was 100 parts by mass was 10.1 parts by mass.

[Preparation Examples 4 to 9]
Oligomers (4) to (9) were obtained in exactly the same manner as in Preparation Example 1, except that the amount and type of each component used were changed as shown in Table 1. The unreacted phenolic compound present in any oligomer was 10% or less when the amount of the phenolic compound before the reaction was 100%. Table 1 also shows the number of parts by mass of the rubber component (a4) when the total of the components (a1) to (a3) is 100 parts by mass.

[Preparation Examples 10 and 11]
As (a1), the above Epicoat 807 was additionally used, and oligomers (10) to (11) were obtained in the same manner as in Preparation Example 1, except that the amount of each component used was changed as shown in Table 2. The unreacted phenolic compound present in any oligomer was 10% or less when the amount of the phenolic compound before the reaction was 100%. Table 2 also shows the number of parts by mass of the rubber component (a4) when the total of the components (a1) to (a3) is 100 parts by mass.

[Preparation Examples 12 and 13]
The epicoat 807: 680 g as the component (a1), the ELM-100: 477 g as the component (a2), the tetramethylbisphenol A 426 as the component (a3), and the WAK104 as the component (a4) Were charged into the reaction vessel in the amounts shown in Table 2, and reacted at 120 ° C. for 8 hours to obtain oligomers (12) to (13). The unreacted phenolic compound present in any oligomer was 10% or less when the amount of the phenolic compound before the reaction was 100%. Table 2 also shows the number of parts by mass of the rubber component (a4) when the total of the components (a1) to (a3) is 100 parts by mass.

[Comparative Preparation Example 1]
(A1) The above-mentioned Epicote 807: 680 g as component, (a2) ELM-100: 397.5 g as component, and (a3) tetramethylbisphenol A: 355 g as component are charged in a reaction vessel at 120 ° C. For 8 hours to obtain an oligomer (14). The unreacted phenol compound present in the oligomer was 10% or less when the amount of the phenol compound before the reaction was 100%. Table 2 also shows the number of parts by mass of the rubber component (a4) when the total of the components (a1) to (a3) is 100 parts by mass.

[Comparative Preparation Example 2]
(A1) The above-mentioned Epicote 807: 680 g as the component, (a2) The above-mentioned ELM-100: 397.5 g, (a3) The above-mentioned tetramethylbisphenol A: 355 g, and (a4) the component The above WAK104) was charged into the reaction vessel in the amount shown in Table 2, and reacted at 120 ° C. for 8 hours to obtain an oligomer (15). The unreacted phenol compound present in the oligomer was 10% or less when the amount of the phenol compound before the reaction was 100%. Table 2 also shows the number of parts by mass of the rubber component (a4) when the total of the components (a1) to (a3) is 100 parts by mass.

[Examples 1 to 18, Comparative Examples 1 to 6]
Each oligomer (1) to (13) as component (A) synthesized in each preparation example, bifunctional epoxy resin as component (B), tetrafunctional epoxy resin as component (C), and (D) The component 4,4′-diaminodiphenylsulfone was blended in the ratios shown in Table 3, and mixed well at 60 ° C. until the whole became uniform to obtain a resin composition.
The obtained resin composition was sandwiched between glass plates and cured at 180 ° C. for 2 hours to obtain a resin plate. The obtained resin plate was measured for bending strength, bending elastic modulus and bending elongation according to JIS K6911. Further, the fracture toughness value (GIC) of the resin was measured according to ASTM D5045 (SENB method), and Tg was evaluated by the TMA method. The results are shown in Table 4.

The obtained resin composition was impregnated with a hot melt method into carbon fiber (manufactured by Mitsubishi Rayon, Pyrofil MR-50K) aligned in one direction, and the basis weight was 145 g / m ² and the resin content was 35% by mass. A directional prepreg (composite intermediate material) was prepared. This prepreg was laminated with [0 °] 10 and [+ 45 ° / 0 ° / −45 ° / 90 °] 4S pseudo-isotropic, and cured at 180 ° C. for 2 hours to obtain a composite material. They were evaluated for 0 ° compressive strength after water absorption at 93 ° C. and compressive strength after impact at room temperature.

  The characteristics of the composite material were determined by the following measurement method. The measurement results were converted to a fiber volume content of 60%. “0 ° compressive strength after water absorption at 93 ° C.” is obtained by a compression test in the 0 ° direction at 93 ° C. in accordance with ASTM D-695 after leaving a laminate of 0 ° 16 layers in 71 ° C. water for 14 days. It was. “Compression strength after impact at room temperature” is based on NASA RP 1092. A panel with a panel size of 4 "x 4" is fixed on a table with a 3 "x 5" hole and 1/2 "in the center. A 4.9 kg weight with an R nose was dropped, an impact strength of 1500 lb · in per inch of plate thickness was applied, and the panel was subjected to a compression test, and the results are summarized in Table 4. It was.

[Comparative Examples 7 and 9]
The oligomers (14) to (15) synthesized in the comparative preparation example and the other components were blended in the ratios shown in Table 3, and mixed thoroughly at 60 ° C. until the whole became uniform to obtain a resin composition. .
The subsequent steps were performed in the same manner as in Example 1, and various measurements and evaluations were performed in the same manner. The results are shown in Table 4.

[Comparative Example 8]
The oligomer (14) synthesized in the comparative preparation example and the other components were blended in the ratios shown in Table 3, and mixed thoroughly at 60 ° C. until the whole became uniform to obtain a resin composition. In this example, BPF307, which is a crosslinked acrylic rubber-modified bisphenol F type epoxy resin, was used as the component (B), but the rubber component contained therein did not react chemically with the component (A). State.
The subsequent steps were performed in the same manner as in Example 1, and various measurements and evaluations were performed in the same manner. The results are shown in Table 4.

In each example, the heat resistance (Tg) of the resin composition, the impact resistance (compressive strength after impact) of the composite material, and the mechanical properties (compressive strength after moisture absorption at 93 ° C.) in a high temperature and high humidity environment are all. The physical properties exceeded the target values. The GIC of the resin composition was also excellent. The target values are 160 ° C. for heat resistance (Tg), 323 MPa for impact resistance (compression strength after impact), and 1100 MPa for mechanical properties (compression strength after moisture absorption at 93 ° C.) in a high temperature and high humidity environment. .
On the other hand, in Comparative Examples 7 and 8 in which the rubber component (a4) was not contained in the component (A), although the heat resistance was good, the impact resistance and the mechanical properties in a high temperature and high humidity environment were poor.
Further, in Comparative Example 11 in which the rubber component (a4) was excessively contained in the component (A), the prepreg could not be produced because the viscosity became very high after the preparation of the resin composition.

Claims (1)

A composite intermediate in which a resin composition is impregnated in a reinforcing fiber,
The resin composition is represented by 20 to 60 mol% of a bifunctional epoxy resin (a1), 20 to 50 mol% of a trifunctional epoxy resin (a2), and 20 to 50 mol% of a general formula (I). It is obtained by reacting a resin component consisting of 100 mol% in total with the phenol compound (a3) and a rubber component (a4) having a functional group capable of reacting with an epoxy group, and has substantially no phenolic hydroxyl group. , An oligomer (A) in which the amount of the rubber component (a4) is 1 to 25 parts by mass with respect to 100 parts by mass of the resin component;
A bifunctional epoxy resin (B);
A tetrafunctional epoxy resin (C);
An aromatic amine compound (D),
When the resin component in the oligomer (A) is 15 to 60 parts by mass, the bifunctional epoxy resin (B) is 10 to 40 parts by mass, and the tetrafunctional epoxy resin (C) is 15 to 75 parts by mass. And the aromatic amine compound (D) is contained in a range where the theoretical equivalent to the epoxy group is 90 to 175%.

(In the formula, X represents a hydrogen atom, an alkyl group having 6 or less carbon atoms, or one selected from the group consisting of Br, and Y represents a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —SO. _2-

1 type selected from the group consisting of )