JP4933790B2 - Epoxy resin composition - 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 properties (compression properties).

  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.

  Furthermore, as a method for improving the impact resistance, Patent Literature 3 proposes a method for improving the delamination strength in a multilayer composite material. This is a method in which the fine particles of thermoplastic resin are intensively distributed between the layers, but this method inevitably reduces the tack level of the prepreg (composite intermediate material) and also complicates the process. As a result, new problems such as complicated quality control occur.

  In addition, as a method for improving impact resistance, a method of inserting a kind of shock absorbing layer called interleaf between layers has been proposed (see Patent Documents 4 to 7), but all of the layers become thicker. There is a possibility that the fiber ratio is lowered, the tensile strength in the direction of 90 ° with respect to the interlayer is remarkably lowered, or the tack level of the prepreg is deteriorated and the handling property is lowered.

Therefore, in the patent document 8, 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 and impact resistance. As a composite material intermediate, we have proposed a technology that uses a resin composition in which a tetrafunctional epoxy resin and an aromatic amine are blended in a reaction product of a bifunctional epoxy resin, a trifunctional epoxy resin, and a phenol compound as a matrix resin. .
JP 58-124126 A JP-A-62-153349 Japanese Unexamined Patent Publication No. 1-110537 U.S. Pat. No. 3,472,730 JP 51-58484 A JP-A-60-63229 JP-A-60-231738 Japanese Patent No. 3026372

Recently, however, market performance requirements for composite materials have been increasing, and materials having both heat resistance and higher impact resistance have been demanded.
Patent Document 8 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, a method of suppressing a decrease in heat resistance by blending a heat-resistant rubber component such as an elastomer can be considered, but the rubber component is uniformly mixed in the state of the resin composition before curing. However, there is a tendency for phase separation to occur due to a decrease in the solubility of the elastomer in the epoxy resin due to the reaction between the epoxy resins during heat curing, or due to a difference in the reaction rate between the epoxy resins and the reaction rate between the elastomer and the epoxy resin. . As a result, the resulting composite material has a significant decrease in properties.

  The present invention has been made in view of the above circumstances, and provides an epoxy resin composition having high heat resistance and impact resistance, which has been difficult to achieve in the past, and suitable for producing a composite intermediate as a matrix resin. The task is to do.

（式（Ｉ）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。）

（式（ＩＩ）中、Ｘは１〜１０、Ｙは１〜１０、Ｚは１〜２０で、いずれも整数である。また、ＰＡは下記式（ＩＩＩ）である。

（式（ＩＩＩ）中、ａは０〜２、ｂは０〜２、ｌは１〜１０で、いずれも整数である。ただし、ａとｂとは同時に０になることはない。また、Ｃ_αは−（ＣＨ_２）_α−（αは２〜４０の整数）である。そして、ＰＡ_１、ＰＡ_２はそれぞれ独立に、下記式（ＩＶ）および／または（Ｖ）であり、ＰＥは下記式（ＶＩ）である。

（式（ＩＶ）、（Ｖ）中、Ｃ_βは−（ＣＨ_２）_β−（βは２〜４０の整数）である。Ｒ_０は−（ＣＨ_２）_ｄ−（ｄは１〜６の整数）である。そして、Ｒ_１、Ｒ_１’はそれぞれ独立に、ＨまたはＣＨ_３である。）

（式（ＶＩ）中、ｍは３〜２０の整数、ｎは１〜１０の整数である。また、Ｒ_２は−（ＣＨ_２）_ｅ−（ｅは２〜８の整数）である。Ｃ_γは−（ＣＨ_２）_γ−（γは２〜４０の整数）である。）
In the epoxy resin composition of the present invention, a bifunctional epoxy resin (a1), a phenol compound (a2) represented by the following formula (I), and a polyamide resin (a3) represented by the following formula (II) are mixed and heated. An epoxy resin component (A) in which 80% or more of the phenolic hydroxyl groups contained in the phenol compound (a2) have reacted;
A bifunctional epoxy resin (B);
A tetrafunctional epoxy resin (C);
An epoxy resin composition containing an aromatic amine compound (D),
The bifunctional epoxy resin (a1) and the phenol compound (a2) are included in a mass ratio of 50 to 80:20 to 50 (provided that (a1) + (a2) = 100) and the polyamide resin ( The content in the epoxy resin component (A) of a3) is 1 to 45% by mass,
Furthermore, when the total of the bifunctional epoxy resin (a1), the phenol compound (a2), the bifunctional epoxy resin (B), and the tetrafunctional epoxy resin (C) is 100 parts by mass, the bifunctional The total amount of the epoxy resin (a1) and the phenol compound (a2) is 15 to 70 parts by mass, the bifunctional epoxy resin (B) is 5 to 30 parts by mass, and the tetrafunctional epoxy resin (C) is 10 to 75 parts. Mass part,
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 (I), X represents one selected from the group consisting of a hydrogen atom, an alkyl group having 6 or less carbon atoms, and Br, and Y represents a direct bond, —CH ₂ —, —C (CH ₃ ) _2. -, - _SO 2 -,

1 type selected from the group consisting of )

(In formula (II), X is 1-10, Y is 1-10, Z is 1-20, and all are integers. PA is the following formula (III).

(In the formula (III), a is 0 to 2, b is 0 to 2, l is 1 to 10, and both are integers. However, a and b are not 0 at the same time. _α is — (CH ₂ ) _α — (α is an integer of 2 to 40), and PA ₁ and PA ₂ are each independently the following formulas (IV) and / or (V), and PE is: Formula (VI).

(In formulas (IV) and (V), _Cβ is — (CH ₂ ) _β — (β is an integer of 2 to 40), R ₀ is — (CH ₂ ) _d — (d is 1 to 6) And R ₁ and R ₁ ′ are each independently H or CH _3. )

(In formula (VI), m is an integer of 3 to 20, n is an integer of 1 to 10. R ₂ is — (CH ₂ ) _e — (e is an integer of 2 to 8). the _gamma - a (gamma is an integer of _{2~40)) - (CH 2)} γ.

  According to the present invention, it is possible to provide an epoxy resin composition having high heat resistance and impact resistance, which has been difficult to achieve in the past, and suitable for producing a composite intermediate as a matrix resin.

Hereinafter, the present invention will be described in detail.
The epoxy resin composition of the present invention is a resin composition containing components (A) to (D) described below as essential components.
[(A) component]
As the component (A), a bifunctional epoxy resin (a1), a phenol compound (a2) represented by the above formula (I), and a polyamide resin (a3) represented by the above formula (II) are mixed and heated. It is an epoxy resin component (A) obtained in this way.
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. Of these, for example, a bisphenol type epoxy resin is represented by the following general formula (VII).

  The phenol compound as the component (a2) satisfies the structural formula (I), 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 polyamide resin as the component (a3) is a polyether ester amide (polyether ester amide block copolymer) represented by the above formula (II). This polyether ester amide is a polymer obtained by reacting a polyamide component with a polyether ester component comprising polyoxyalkylene glycol and dicarboxylic acid, and having a amide bond, an ether bond and an ester bond in the molecular chain. In addition, it exhibits high compatibility with epoxy resins and has low moisture absorption in a high temperature and high humidity environment. Therefore, by selecting this polyether ester amide, it is possible to provide an epoxy resin composition or a composite material that satisfies not only high heat resistance and impact resistance, but also mechanical properties in a high temperature and high humidity environment.

In formula (II), PA is represented by the above formula (III), and PE is represented by the above formula (VI). In formula (III), PA ₁ and PA ₂ are each independently the above formula (IV) and / or formula (V). That is, both PA ₁ and PA ₂ are those having the structure of formula (IV) alone, those having the structure of formula (V) alone, those having the structure of formula (IV), and formula (V). In some cases, the same structure is used.

In the formula (II), X is 1 to 10, Y is 1 to 10, Z is 1 to 20, and all are integers. In formula (III), a is 0-2, b is 0-2, l is 1-10, and all are integers. However, a and b are not 0 at the same time. C _α is — (CH ₂ ) _α — (α is an integer of 2 to 40).

Moreover, in formula (IV) and (V), _Cβ is — (CH ₂ ) _β — (β is an integer of 2 to 40). R ₀ is — (CH ₂ ) _d — (d is an integer of 1 to 6). R ₁ and R ₁ ′ are each independently H or CH ₃ .

Furthermore, in Formula (VI), m is an integer of 3-20, n is an integer of 1-10. R ₂ is — (CH ₂ ) _e — (e is an integer of 2 to 8). C _γ is — (CH ₂ ) _γ — (γ is an integer of 2 to 40).

  As a method for producing the polyether ester amide, any method can be adopted as long as a uniform and high molecular weight polymer can be obtained. For example, first, a method of synthesizing a polyamide oligomer, adding polyoxyalkylene glycol and dicarboxylic acid thereto, and heating under reduced pressure to increase the degree of polymerization can be mentioned.

Moreover, as such a polyether ester amide, a commercial item can also be used. Examples of commercially available polyether ester amides include TPAE series (TPAE12, TPAE31, TPAE32, TPAE38, TPAE8, TPAE10, TPAE100, TPAE23, TPAE63, TPAE200, TPAE201, TPAE260, and TPAE260) manufactured by Fuji Kasei Kogyo.
Among these, TPAE32 is a mixture of those represented by the formula (II), and in the formulas (II) to (VI), the average values are X = Y = 1, Z = 7.26, a = 0.16. , B = 0.84, l = 2.23, α = 10, β = 34, d = 2, m = 14, n = 1, γ = 10, e = 4. R ₁ and R ₁ ′ are both H. Further, in TPAE 32, both PA ₁ and PA ₂ are in a state where a structure of formula (IV) and a structure of formula (V) are mixed.
Further, TPAE12 is a mixture of those represented by formula (II), although the structural formula of polyamide is different from that of TPAE32. In formulas (II) to (VI), X = Y = 1, Z = 7.26, a = 0.16, b = 0.84, l = 2.23, α = 10, β = 34, d = 2, m = 14, n = 1, γ = 10, e = 4 is there. R ₁ and R ₁ ′ are both Further, in TPAE 12, both PA ₁ and PA ₂ are in a state where a structure of formula (IV) and a structure of formula (V) are mixed.

  The epoxy resin component (A) is obtained by mixing and heating the component (a1), the component (a2), and the component (a3) described above. During heating, a catalyst may be added as necessary. Moreover, it is necessary to perform the heating here so that 80% or more of the phenolic hydroxyl group contained in the phenol compound (a2) reacts and only 20% or less remains. If the phenolic hydroxyl group exceeding 20% remains unreacted, the water resistance and storage stability of the epoxy resin component (A) and the epoxy resin composition containing the epoxy resin component (A) are significantly reduced. Preferably, the reaction rate of the phenolic hydroxyl group is 90% or more.

  As a preparation method of the epoxy resin component (A), 80% or more of the phenolic hydroxyl groups react with the mixture of the components (a1) to (a3) as described above, and preferably the reaction proceeds relatively gently. Heating may be performed under various conditions. Specifically, when the catalyst is not used, the mixture is heated at 100 to 150 ° C. for 5 to 24 hours, and when the catalyst is used, the condition for heating the mixture at 100 to 130 ° C. for 2 to 6 hours is appropriate. .

  As a more preferable method for preparing an epoxy resin component, the (a1) component and the (a3) component are mixed in advance and heated at 130 to 180 ° C. for 1 to 6 hours, and the (a1) component is mixed with the (a3) component. At least a part is dissolved, and then the phenol compound (a2) is added and heated at 120 to 150 ° C. for 1 to 6 hours when no catalyst is used, and at 100 to 130 ° C. for 1 to 6 hours when a catalyst is used. A two-stage preparation method is mentioned. By containing the epoxy resin component (A) obtained by such a preparation method, the epoxy resin composition has high heat resistance and impact resistance, and is suitable for a matrix resin of a composite material intermediate. Become.

  In addition, as a catalyst used at the time of preparation of an epoxy resin component (A), if it accelerates | stimulates the reaction of an epoxy group and a phenolic hydroxyl group moderately, there will be no restriction | limiting in particular, A triphenylphosphine (TPP) is especially preferable. What is necessary is just to set the quantity of a catalyst suitably so that reaction may advance smoothly.

  The epoxy resin component (A) can be prepared as described above, and the ratio of each component at that time is such that the bifunctional epoxy resin (a1) and the phenol compound (a2) are 50 to 80:20 by mass ratio. 50 (however, (a1) + (a2) = 100) is required. The polyamide resin (a3) needs to be contained in an amount of 1 to 45% by mass in the epoxy resin component (A).

By setting the ratio of each component in such a range, it is possible to achieve both impact resistance and heat resistance of the finally obtained epoxy resin composition.
Here, when the sum of the bifunctional epoxy resin (a1) and the phenol compound (a2) is 100, the impact resistance of the epoxy resin composition becomes sufficient by setting the ratio of the component (a1) to 50 or more, By setting it as 80 or less, the heat resistant fall of an epoxy resin composition can be suppressed. Further, if the ratio of the phenol compound (a2) is 20 or more, sufficient impact resistance and heat resistance can be obtained, and if it is 50 or less, gelation does not occur during the preparation of the epoxy resin component (A). 20% or more of the phenolic hydroxyl group does not remain unreacted.
If the ratio of the polyamide resin (a3) is 1% by mass or more in the component (A), the impact resistance of the epoxy resin composition is sufficient, and if it is 45% by mass or less, the epoxy resin composition The viscosity of the product can be kept low, and the production process passability when producing a prepreg using this can be improved. Furthermore, the ratio in the (A) component of a preferable polyamide resin (D) is 5-35 mass%.

By preparing the epoxy resin component (A) in this way, the phenolic compound (a2) and the polyamide resin (a3) are each an island phase (soft segment), and the bifunctional epoxy resin (a1) is a sea phase (hard). The morphological control of the sea-island structure is possible.
Thus, when the polyamide resin (a3) is fixed as an island phase in the epoxy resin component (A), the polyamide resin (a3) does not phase-separate and the epoxy resin component serves as the island phase that plays the role of the soft segment. As a result, the resulting epoxy resin composition exhibits very high impact resistance. Furthermore, as a soft segment, in addition to the island phase composed of the polyamide resin (a3), an island phase composed of the phenol compound (a2) also exists. Therefore, the synergistic effect of each soft segment is expressed, and the impact resistance of the resulting epoxy resin composition is greatly improved as compared with the case where the soft segment is composed of only one of them.

Moreover, since the bifunctional epoxy resin (a1) is adopted as the epoxy resin used for the component (A) and the polyether ester amide of the formula (II) is adopted as the polyamide resin (a3), the component (a3) (A1) The solubility in the component is very high, and the component (A3) can contain the component (a3) at a high content, and together with such a component (A), heat resistance can be expressed as described later. By using the tetrafunctional epoxy resin (C) and the later-described component (D) that acts as a curing agent as the sea phase, the resulting epoxy resin composition has a heat resistance in addition to the improvement in impact resistance as described above. It is also excellent in properties.
That is, when the obtained epoxy resin composition is cured, the resin fracture toughness value (GIC), which is an index of impact resistance, is dramatically improved to 450 J / m ² or more, and heat which is an index of heat resistance. The transition point (G′-Tg) was 160 ° C. or higher, and it was possible to achieve both heat resistance and impact resistance.

[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.

[Epoxy resin composition]
The epoxy resin composition of the present invention contains the components (A) to (D) described above. The content of each component is bifunctional when the total of the bifunctional epoxy resin (a1), the phenol compound (a2), the bifunctional epoxy resin (B), and the tetrafunctional epoxy resin (C) is 100 parts by mass. The total amount of the epoxy resin (a1) and the phenol compound (a2) is 15 to 70 parts by mass, the bifunctional epoxy resin (B) is 5 to 30 parts by mass, and the tetrafunctional epoxy resin (C) is 10 to 75 parts by mass. It is necessary to be a part. Moreover, content of an aromatic amine compound (D) is the range from which the theoretical equivalent with respect to the epoxy group calculated from following formula (VIII) becomes 90 to 175% equivalent.
When the ratio of the components (A) to (C) is outside these ranges, it is difficult to achieve both high heat resistance and impact resistance. 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 total amount of the bifunctional epoxy resin (a1) and the phenol compound (a2) is 20 to 65 parts by mass, the bifunctional epoxy resin (B) is 10 to 25 parts by mass, and the tetrafunctional epoxy resin (C ) Is 10 to 60 parts by mass, and the content of the aromatic amine compound (D) is such that the theoretical equivalent is 100 to 150% equivalent.

In the epoxy resin composition, other epoxy resins (E) can be used in combination as long as the balance of physical properties is not lost. 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. In addition, epoxy resins obtained by modifying these epoxy resins with bromine or the like to impart flame retardancy can be preferably used, but are not limited thereto.
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 epoxy resin composition includes a so-called elastomer component such as a butadiene-acrylonitrile copolymer having carboxyl groups at both ends, and a thermoplastic resin such as polyethersulfone, polysulfone, polyetheretherketone, polyetherimide, and polyvinyl butyrate. Even if you use the ingredients together according to 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 an epoxy resin composition include carbon fibers, glass fibers, aramid fibers, boron fibers, silicon carbide fibers, and the like. These include milled fibers, chopped fibers, continuous fibers, and various types. It can be used in the form of a woven fabric or the like. Among these, carbon fibers having a tensile strength of 350 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.
A method for impregnating the reinforcing fiber with the epoxy resin composition is not particularly limited, and a normal method may be used.
According to the composite intermediate material obtained by impregnating the reinforcing resin with the above-described epoxy resin composition, a composite material satisfying high heat resistance and impact resistance, which has been difficult in the past, can be provided.

Hereinafter, the present invention will be described specifically by way of examples.
In addition, it shows below about each used component.

Component (a1) and component (B) Epicoat 807 (Ep807): manufactured by Japan Epoxy Resin Co., Ltd., bisphenol F type epoxy resin, average molecular weight: about 312
Epicoat 828 (Ep828): Japan Epoxy Resin, bisphenol A type epoxy resin, average molecular weight: about 340
Component (a2) 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)
Component (a3)-TPAE12: manufactured by Fuji Kasei Kogyo Co., Ltd., polymerized fatty acid-based polyether ester amide-TPAE32: manufactured by Fuji Kasei Kogyo Co., Ltd., polymerized fatty acid-based polyether ester amide (C) component-Epicoat 604: Japan Epoxy Resin Co., Ltd. Manufactured, TGDDM, average molecular weight 302
MY721: manufactured by Huntsman, TGDDM, average molecular weight 302
Component (D) DDS: 4,4′-diaminodiphenylsulfone Seika Cure S manufactured by 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 of epoxy resin component (A)]
(Preparation Example 1)
Components (a1) to (a3) were charged into the reaction vessel at a mass ratio shown in Table 1.
Specifically, the component (a1) was 500 g, the component (a2) was 500 g, and the component (a3) was 7.2 g. Next, this was heated at 180 ° C. for 4 hours and then cooled to 120 ° C., 1 g of TPP was charged as a catalyst, and maintained at 120 ° C. for 2 hours to prepare an epoxy resin component 1.
The peak resulting from tetramethylbisphenol A in the epoxy resin obtained by this reaction was 10% or less, assuming that the peak before the reaction was 100%.

(Preparation Examples 2 to 8)
Components (a1) to (a3) were charged into a reaction vessel at a mass ratio shown in Table 1, and heated at 180 ° C. for 4 hours. Thereafter, the mixture was cooled to 120 ° C., TPP was charged as a catalyst, and maintained at 120 ° C. for 2 hours to prepare an epoxy resin component. The tetramethylbisphenol A present in the epoxy resin component was 10% or less when the amount of the phenol compound before the reaction was 100%. The catalyst amount was an amount corresponding to 0.1% by mass of the total amount of the components (a1) to (a3).
The products obtained in Preparation Examples 2 to 8 are referred to as epoxy resin components 2 to 8.

(Preparation Example 9)
Each component was charged into the reaction vessel at the compounding ratio shown in Table 1.
Specifically, the component (a1) was 500 g, the component (a2) was 500 g, and the component (a3) was not used. Subsequently, after heating this at 120 degreeC for 2 hours, 1 g of TPP was prepared as a catalyst, and it hold | maintained at 120 degreeC for 2 hours, and prepared the epoxy resin component 9. The peak resulting from tetramethylbisphenol A in the epoxy resin obtained by this reaction was 10% or less, assuming that the peak before the reaction was 100%.

(Preparation Example 10)
Each component was charged into the reaction vessel at the compounding ratio shown in Table 1.
Specifically, the component (a1) was 800 g, the component (a2) was 200 g, and the component (a3) was 900 g. Subsequently, after heating this at 180 degreeC for 4 hours, 2g of TPP was prepared as a catalyst, and it hold | maintained at 180 degreeC for 1 hour, and was set as the epoxy resin component 10. The peak resulting from tetramethylbisphenol A in the epoxy resin obtained by this reaction was 10% or less, assuming that the peak before the reaction was 100%.

(Preparation Example 11)
Each component was charged into the reaction vessel at the compounding ratio shown in Table 1.
Specifically, the component (a1) was 500 g, the component (a2) was 500 g, and the component (a3) was 102 g. Subsequently, this was heated at 180 ° C. for 4 hours to obtain an epoxy resin component 11. As a result of measuring the thus obtained product by GPC, the peak due to tetramethylbisphenol A almost disappeared.

[Examples 1-12, Comparative Examples 1-9]
The epoxy resin components 1 to 11 synthesized in each preparation example, the component (B), the component (C), and the component (D) are blended as shown in Table 2 until the whole becomes uniform at 60 ° C. Thorough mixing was performed to obtain an epoxy resin composition.
The obtained epoxy resin composition was defoamed and then sandwiched between glass plates and cured at 180 ° C. for 2 hours to obtain a resin plate. About the obtained resin board, the fracture toughness value (GIC) was measured based on ASTM D5045 SENB method, and G'-Tg (thermal transition point) was measured by TMA method. These results are shown in Table 2.

The obtained epoxy resin composition was impregnated in one direction with carbon fiber (manufactured by Mitsubishi Rayon, Pyrofil MR50K) by a hot melt method, and the carbon fiber 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 in a [+ 45 ° / 0 ° / −45 ° / 90 °] 4S pseudo-isotropic state and cured at 180 ° C. for 2 hours using an autoclave to obtain a composite material.
About the obtained composite material, the compressive strength after impact at room temperature was measured as follows. The results are shown in Table 2.

(Measurement of compressive strength after impact (CAI))
In accordance with NASA RP 1092, a composite material cut to a panel size of 4 "x 4" was fixed on a table with a 3 "x 5" hole, and a 1/2 "R nose was attached to the center. A weight of 4.9 kg was dropped, an impact strength of 1500 lb · in per inch of plate thickness was added, and then the panel was subjected to a compression test.

In each example, the heat resistance (G′-Tg) and impact resistance (GIC) of the epoxy resin composition, and the physical properties of both the impact resistance (compression strength after impact) of the composite material exceed the target values. Was showing. The target values are 160 ° C. for heat resistance (G′−Tg), 450 J / m ^{2 for} GIC, and 196 MPa for impact resistance (compression strength after impact).
On the other hand, in Comparative Examples 1 to 6 in which the ratio of the components (A) to (D) is out of the scope of the present invention, at least one of heat resistance (G′-Tg), GIC, and impact resistance (compression strength after impact). Did not reach the target value.
Further, in Comparative Example 7 in which the polyamide resin (a3) is not contained in the component (A), GIC is insufficient, and in Comparative Example 8 that is excessively contained, the epoxy resin composition has a very high viscosity after its preparation. The prepreg could not be produced because it became high. In the comparative example 9 in which the phenolic hydroxyl group remains unreacted and remains in the component (A) in a large amount, the polyamide resin undergoes phase separation after the preparation of the epoxy resin composition, so the characteristics of the resin plate of the epoxy resin composition Of course, the properties of the composite material could not be evaluated and measured.

Claims (1)

A bifunctional epoxy resin (a1), a phenol compound (a2) represented by the following formula (I) and a polyamide resin (a3) represented by the following formula (II) are mixed and heated, and the phenol compound (a2) An epoxy resin component (A) in which 80% or more of the phenolic hydroxyl groups contained are reacted;
A bifunctional epoxy resin (B);
A tetrafunctional epoxy resin (C);
An epoxy resin composition containing an aromatic amine compound (D),
The bifunctional epoxy resin (a1) and the phenol compound (a2) are included in a mass ratio of 50 to 80:20 to 50 (provided that (a1) + (a2) = 100) and the polyamide resin ( The content in the epoxy resin component (A) of a3) is 1 to 45% by mass,
Furthermore, when the total of the bifunctional epoxy resin (a1), the phenol compound (a2), the bifunctional epoxy resin (B), and the tetrafunctional epoxy resin (C) is 100 parts by mass, the bifunctional The total amount of the epoxy resin (a1) and the phenol compound (a2) is 15 to 70 parts by mass, the bifunctional epoxy resin (B) is 5 to 30 parts by mass, and the tetrafunctional epoxy resin (C) is 10 to 75 parts. Mass part,
The epoxy resin composition, wherein the aromatic amine compound (D) is contained in a range of 90 to 175% of a theoretical equivalent to an epoxy group.

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

1 type selected from the group consisting of )

(In formula (II), X is 1-10, Y is 1-10, Z is 1-20, and all are integers. PA is the following formula (III).

(In the formula (III), a is 0 to 2, b is 0 to 2, l is 1 to 10, and both are integers. However, a and b are not 0 at the same time. _α is — (CH ₂ ) _α — (α is an integer of 2 to 40), and PA ₁ and PA ₂ are each independently the following formulas (IV) and / or (V), and PE is: Formula (VI).

(In formulas (IV) and (V), _Cβ is — (CH ₂ ) _β — (β is an integer of 2 to 40), R ₀ is — (CH ₂ ) _d — (d is 1 to 6) And R ₁ and R ₁ ′ are each independently H or CH _3. )

(In formula (VI), m is an integer of 3 to 20, n is an integer of 1 to 10. R ₂ is — (CH ₂ ) _e — (e is an integer of 2 to 8). _γ is — (CH ₂ ) _γ — (γ is an integer of 2 to 40).)