JPH0643508B2 - Prepreg and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention is a prepreg having heat resistance and excellent impact resistance, and a method for producing the same. More specifically, for a composite material that uses a high-strength carbon fiber or the like as a reinforcing material and provides a molded product that has both the excellent mechanical properties and thermal properties of an epoxy resin and the excellent toughness of a thermoplastic resin. The present invention relates to a prepreg that can be preferably used and a method for producing the same.

[Prior art and problems]

In recent years, composite materials using carbon fibers, aromatic polyamide fibers, etc. as reinforcing materials have been widely used as structural materials for aircraft and the like by utilizing their high specific strength and specific rigidity.
Even in an epoxy resin-based prepreg, a combination of an aromatic glycidyl amine type epoxy resin and a diaminodiphenyl sulfone curing agent system as a matrix resin,
We have provided composite materials with excellent heat resistance, mechanical properties, dimensional stability, chemical resistance, and weather resistance.

As described above, the composite material made of the epoxy resin-based prepreg was confirmed to have good performance,
On the other hand, it has been pointed out that the toughness and impact resistance of the composite material are inferior because the matrix resin has low elongation and is brittle, and improvement thereof has been demanded. In particular, when these composite materials are used for aircraft primary structural materials, they may be impacted from the outside due to jumping up of pebbles during takeoff and landing, dropping of tools during maintenance, etc. It is necessary to improve the impact resistance without doing so, but this has been an important issue that is difficult to solve.

When trying to improve the prepreg with impact resistance, it goes without saying that the elongation of the reinforcing material such as carbon fiber is improved, but it is an important point to increase the toughness of the matrix resin used for the prepreg. It has been pointed out that many attempts have been made to improve the matrix resin.

As a means for improving the toughness of the matrix resin for prepreg, a method of mixing a rubber component with an epoxy resin, a method of mixing a high molecular weight component, a method of mixing a filler, and the like have been considered.

However, in the case of the method of mixing the rubber component with the epoxy resin, the toughness and impact resistance of the molded product are improved,
The blending amount is regulated because the heat resistance and mechanical properties are lowered, and the blending amount remains low depending on the application, and a sufficient modifying effect is not given. In addition, in the case of a method of mixing a high molecular weight component with an epoxy resin, for example, when a high molecular weight thermosetting resin such as a phenoxy resin is added, the amount of the compound is regulated in terms of heat resistance similarly to the rubber component, which is improved. The effect is insufficient.

As a method of mixing a thermoplastic resin with an epoxy resin,
A method of putting the thermoplastic resin in a fine powder form into the epoxy resin, or a method of dissolving the thermoplastic resin in a solvent and then mixing this liquid with the epoxy resin have been adopted. However, the composition was non-uniform and the mechanical properties tended to deteriorate. In addition, when mixing with a solvent, there are drawbacks such as a problem in desolvation after mixing, a troublesome preparation method, and a small amount of residual solvent decreasing heat resistance. When a filler is mixed, if it is added in a large amount, the tackiness of the prepreg deteriorates and the handling becomes very poor, or the functional group in the filler acts on the epoxy resin and the storage stability of the prepreg becomes poor. It had drawbacks.

Therefore, as the matrix resin of the prepreg for fiber-reinforced composite materials, conventionally, rubber components, high molecular weight components, fillers, etc. have been included in small amounts, but the conventional method does not cause a decrease in heat resistance, but has a high impact resistance. The improvement effect was poor.

[Object of the Invention]

It is an object of the present invention to provide a prepreg that overcomes the above problems and provides excellent heat resistance and mechanical properties such as toughness and impact strength to a composite material, and a method for producing the prepreg. That is, to provide a prepreg which is impregnated with a uniform epoxy resin / thermoplastic resin mixture composition as a matrix resin and which can be suitably used for a hot melt type fiber reinforced composite material having the advantages of both resins, and a method for producing the same. It is in.

[Structure and Effect of Invention]

The present invention contains the following [A], [B], [C] and a curing agent for an epoxy resin as main components, and [A], [B], [C]
Is a prepreg obtained by impregnating a reinforcing material with a resin composition having a ratio of each component of 30 to 96% by weight, 2 to 50% by weight, and 2 to 49% by weight.

[A] Epoxy resin [B] Thermoplastic resin [C] Epoxy resin other than the above-mentioned epoxy resin having thermoplastic resin solubility and / or a reactive diluent having an epoxy group. [B] [C] and a curing agent for epoxy resin as main components and [A], [B],
The ratio of each component of [C] is 30 to 96% by weight, and 2 to 50, respectively.
A method for producing a prepreg, characterized in that a reinforcing material is impregnated with a resin composition in an amount of 2% to 49% by weight by a hot melt method.

[A] Epoxy resin [B] Thermoplastic resin [C] Epoxy resin other than the above-mentioned epoxy resin having thermoplastic resin solubility and / or reactive diluent having epoxy group Resin composition (matrix resin composition) according to the present invention object)
Then, the [C] component dissolves the [B] component,
Since the component acts as a medium between the [A] component and the [B] component,
A matrix composition of an epoxy resin component / thermoplastic resin component for hot melt which is easy to prepare and is solvent-free and uniform can be provided. Therefore, the prepreg obtained from the prepreg can give a molded article having improved toughness and accompanying impact resistance without impairing the excellent mechanical properties and heat resistance of the epoxy resin component.

As the reinforcing material in the present invention, carbon fiber, glass fiber, aromatic polyamide fiber or the like having an elongation of 1.3% or more is preferable. Generally, glass fibers and aromatic polyamide fibers have an elongation of 2.5% or more. When carbon fibers having an elongation of less than 1.3% are used, the impact properties of the composite material may be slightly insufficient.

Tensile strength of 40 to improve the mechanical properties of composites
Carbon fiber with medium elasticity and high strength of 0 kgf / mm ² or more and elastic modulus of 30 T / mm ² may be used.

In the resin composition of the present invention, the epoxy resin component of component [A] is a glycidylamine type epoxy resin, a novolac type epoxy resin, a bisphenol A type epoxy resin, a urethane modified bisphenol A type epoxy resin, an alicyclic epoxy resin, or the like. Or a mixed epoxy resin. The glycidyl amine type epoxy resin may be M
There are Y720 (manufactured by Ciba Geigy), Epototo YH434 (manufactured by Toto Kasei), YDM120 (manufactured by Toto Kasei) and the like.

Of the above novolac type epoxy resins, phenol
Examples of the novolac type epoxy resin include Epicoat 152, Epicoat 154 (manufactured by Shell Chemical Co., Ltd.), Dow epoxy DEN431, DEN43, DEN439 (manufactured by Dow Chemical Co.), EPPN201 (manufactured by Nippon Kayaku Co., Ltd.), Epicron N740.
(Manufactured by Dainippon Ink and Chemicals, Inc.) and the like.
As a novolac type epoxy resin, Araldite EC
Examples include N1235, ECN1273, ECN1280 (manufactured by Ciba Geigy), EOCN102, EOCN103, EOCN104 (manufactured by Nippon Kayaku Co., Ltd.).

Examples of the bisphenol A type epoxy resin include Epicoat 815, Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1002 (manufactured by Shell Chemical Co., Ltd.) and the like.

Examples of the urethane-modified bisphenol A type epoxy resin include ADEKA RESIN EPU-6, EPU-10, EPU-15
(Manufactured by Asahi Denka Co., Ltd.) and the like, and as the alicyclic epoxy resin, Araldite CY-179, CY-178, CY-182,
Examples include CY-183 (manufactured by Ciba Geigy).

The epoxy resin as the component (A) in the present invention may be used alone or in combination of two or more kinds.

Examples of the curing agent for the epoxy resin include aromatic amines, dicyandiamide, dibasic acid dihydrazide, boron trifluoride complex salts, acid anhydrides, and imidazoles, either alone or in combination.

Examples of the aromatic amines include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and metaxylenediamine.

Examples of the boron trifluoride complex salts include BF ₃ monoethylamine and B ₃ benzylamine.

Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic acid anhydride, and the like.

Examples of the above-mentioned imidazoles include 2-ethyl-4methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2-phenylimidazole and the like.

These curing agents may be used alone or in combination of two or more. Further, as a curing accelerator, a urea compound (for example, 3 [3,4-dichlorophenyl] -1,1-dimethylurea) or an organic metal salt (for example, Co [III] acetylacetonate) is used in combination. You can also do it.

Examples of the thermoplastic resin as the component (B) include polycarbonate, polyetherketone, polysulfone, polyethersulfone, polyetherimide, aromatic polyester, and the like. Of these, polycarbonate, polysulfone, polyethersulfone, polyetherimide, Aromatic polyesters are preferred from the viewpoint of uniform mixing. These thermoplastic resins can be used in combination of two or more kinds.

From the viewpoint of resin preparation, it is preferable that these thermoplastic resin [B] components are in the form of powder having a particle diameter of 400 μm or less, particularly 100 μm or less. Further, those having a glass transition temperature of 100 ° C. or higher are preferable in terms of heat resistance.

Among the components [C] in the present invention, epoxy resins other than the component [A] having a thermoplastic resin-dissolving ability include glycidyl ester type epoxy resins (for example, Epicoat 191 manufactured by Shell Chemical Co., Ltd.), glycidyl amine type epoxy resins ( For example, GOT and GAN manufactured by Nippon Kayaku Co., Ltd., etc., and these epoxy resins are epoxy resins other than the epoxy resin actually blended as the component [A].

Among the reactive diluents having the ability to dissolve the thermoplastic resin as the component [C], the diepoxy compounds include diglycidyl ether, butanediol glycidyl ether, 2-glycidylphenyl glycidyl ether, resorcinol diglycidyl ether, and hexanediol diglycidyl ether. , Polypropylene glycol diglycidyl ether and the like, and the monoepoxy compound includes alkylphenol glycidyl ether, phenyl glycidyl ether, butyl glycidyl ether, cresol glycidyl ether, styrene oxide and the like.

These [C] components can be used in combination of two or more kinds. Further, it is preferable to use one having a viscosity at 25 ° C. of 150 poise or less. This is because, in general, when the thermoplastic resin is dissolved, the resin viscosity becomes high and the handleability of the obtained prepreg is deteriorated. However, when the viscosity of the component (A) is low or the amount of the thermoplastic resin to be mixed is small and there is no problem in handling, such consideration is not necessary.

The combination of the [B] component and the [C] component is required to have a relationship in which the [C] component dissolves the [B] component. If there is no such relationship, the resin composition is considered to be uniform. Therefore, the object of the present invention cannot be achieved.

An example of the combination of the component [C] which is compatible with the component [B] is shown below.

In the combination of [A] component / [B] component / [C] component, in order to simplify the preparation method, the [B] component is previously dissolved in the [C] component, and then the [A] component is added. It is preferable to take.

The mixing ratio of [A] component / [B] component / [C] component is 30 to 96% by weight of [A], [B] and [C], respectively.
˜50 wt%, 2-49 wt%. Particularly preferably, the component [B] is 10 to 30% by weight, and the component [C] is 5 to 30% by weight.

When the blending amount of the component (B) is more than 50% by weight, the melt viscosity becomes high, which makes roll mill mixing difficult, and
Imperfect impregnation between fibers occurs during prepreg production, and it is difficult to obtain a good prepreg. If the blending amount of the component [C] is more than 49% by weight, the heat resistance of the obtained composite material is extremely lowered and the mechanical properties are also lowered, which is not preferable. [B]
If the amount of each of the component and the component [C] is less than 2% by weight, the object of the present invention cannot be achieved. The ratio of [B] component / [C] component is preferably 2 or less. When the ratio is more than 2, the viscosity of the composition increases and the handleability is poor, and when it is used as a prepreg, the impregnating property between fibers decreases and the tack is low, which is not preferable. Moreover, the mechanical properties are deteriorated. It is preferable that the blending amount of the component [C] is kept to a minimum so that the matrix resin composition has a uniform composition in relation to the blending amount of the component [B].

In the resin composition of the present invention, in addition to the above-mentioned essential components, a small amount of a rubber component (for example, a carboxyl group-terminated butadiene-acrylonitrile copolymer, nitrile rubber, etc.) and a prepreg are handled. A filler (for example, silica powder), a flame retardant such as antimony trioxide, or a coloring agent may be added to such an extent that the property is not deteriorated.

The resin composition in the present invention can be prepared, for example, by the following method.

That is, each component is supplied to a kneading device, and preferably kneaded by heating under an inert gas atmosphere. The heating temperature at this time is lower than the curing start temperature of the epoxy resin. Alternatively,
After dissolving the component [B] in the component [C], the component [A] and the like are added and kneaded. At this time, the component [B] is dissolved in a part or all of the component [C], and when there is a balance of the component [A] and the component [C], the remaining component [C] is separated from the component [A] or It is preferable to previously mix with the component (A) and then knead in order to reduce the heat history applied to the resin composition and quickly obtain a uniform resin composition. In either case, the epoxy resin curing agent component should be added last and kneaded. It is usually prepared at a temperature of 20 to 200 ° C, particularly preferably at a temperature of 50 to 150 ° C.

In the present invention, when the reinforcing material fibers are impregnated with the prepreg resin composition to form a prepreg, the so-called hot melt method, which is already known, is used.

The resin composition in the present invention is a resin composition in which the respective components are uniformly mixed because the component [C] intervenes as a medium between the epoxy resin of the component [A] and the thermoplastic resin of the component [B]. Moreover, it is an excellent resin composition suitable for prepreg, which is not affected by the residual solvent and has both excellent heat resistance of epoxy resin and toughness / impact strength of thermoplastic resin.

Also, due to solubility problems, when a uniform mixture of the [B] component and the [C] component is mixed with the [A] component, the [B] component may be deposited as a layer having a certain size. However, it goes without saying that even in that case, the mixed state is more uniform than when the components [A] and [B] are simply mixed.

The unidirectional prepreg or the woven prepreg obtained by such an operation is good in quality.

[Examples and Comparative Examples]

Examples 1 to 5 and Comparative Examples 1 to 5 [A], [B] and [C] components are added to a uniform mixture of the types and blending ratios shown in Table 2 and further cured in the types and blending ratios shown in Table 2. The component was added to obtain a resin composition for prepreg. A resin film was produced from this composition using a film coater, and carbon fiber Vesfite IM-500 (manufactured by Toho Rayon Co., Ltd., tensile strength 500 kgf / m) was formed on the resin film.
m ² and elastic modulus 30 T / mm ² ) were arranged, heated and impregnated to obtain a unidirectional pyripreg having a carbon fiber areal weight of 150 g / m ² and a resin content of 34% by weight.

A predetermined number of prepregs were cut and laminated from this prepreg, and a test piece was cut out from a molded plate that was heat-cured by autoclave molding, and the glass transition temperature, 0 ° interlaminar shear strength, 0 ° compressive strength, 750in- The damaged area after 1b / in impact and the compressive strength after impact were measured. The results are shown in Table 2.

As a comparative example, a system containing no component [B], [B]
With regard to the system containing no component [C], a prepreg was prepared and molded under the same conditions as in the examples, and the physical properties were measured. The results obtained are shown in Table 2.

From the above results, in the case of Examples 1 to 5, Comparative Examples 1 to 5
750in-1b / although the thermal and mechanical properties are not so different compared to
Since the damage area during impact is small and the compressive strength after impact is high, it is clear that the composite material has excellent impact resistance.

Examples 6 to 7 Highly compounded systems of the component [B], which were prepared by mixing the component [B] with the component [C] in advance in the types and blending ratios shown in Table 2 and mixing them by heating with stirring at 110 ° C. for 1 hour. A uniform mixture of the components [B] and [C] was obtained even in a system in which the content of the component [C] was suppressed. Furthermore, the [A] component and the curing agent component having the types and blending ratios shown in Table 2 were added, and the mixture was roll-milled at 80 ° C. for 1 hour to obtain a prepreg resin composition. After that, a prepreg was made in the same manner as in Examples 1 to 5. Example 1
Molded plates were prepared in the same manner as described above to measure the composite characteristics. As shown in Table 2, it was revealed that these are composite materials having excellent impact resistance.

Claims (12)

[Claims] 1. The following [A], [B], [C] and a curing agent for epoxy resin are contained as main components, and [A], [B],
The ratio of each component of [C] is 30 to 96% by weight, and 2 to 50, respectively.
A prepreg obtained by impregnating a reinforcing material with a resin composition in an amount of 2 to 49% by weight. [A] Epoxy resin [B] Thermoplastic resin [C] Epoxy resin other than the above-mentioned epoxy resin capable of dissolving the thermoplastic resin and / or reactive diluent having an epoxy group 2. The epoxy resin as the component (A) is a glycidylamine type epoxy resin, a novolac type epoxy resin, a bisphenol A type epoxy resin, a urethane-modified bisphenol A type epoxy resin, or an alicyclic epoxy resin, alone or as a mixed epoxy resin. The prepreg according to claim (1). 3. The prepreg according to claim 1, wherein the thermoplastic resin as the component (B) is polycarbonate, polysulfone, polyethersulfone, polyetherimide, or aromatic polyester. 4. A glycidyl ester type epoxy resin and a glycidyl amine type epoxy resin having a viscosity of 150 poise (temperature: 25 ° C.) or less, as the component (C), which is capable of dissolving a thermoplastic resin. ) The prepreg described in the section above. 5. The reactive diluent having an epoxy group as the component [C] is, as a diepoxy compound, diglycidyl ether, butanediol glycidyl ether, 2-glycidylphenyl glycidyl ether, resorcinol diglycidyl ether, hexanediol diglycidyl ether. , Polypropylene glycol diglycidyl ether, as a monoepoxy compound, alkylphenol glycidyl ether, phenyl glycidyl ether,
Claims (1) which are butyl glycidyl ether, cresol glycidyl ether, and styrene oxide.
The prepreg described in the item. 6. The prepreg according to claim 1, wherein the ratio of [B] component / [C] component is 2 or less. 7. The thermoplastic resin as the component [B] is polysulfone, polyether sulfone, or polyetherimide, and the epoxy resin having the ability to dissolve the thermoplastic resin as the component [C] and / or the reactivity having an epoxy group. Diluent is diglycidyl aniline, diglycidyl toluidine, phenyl glycidyl ether, butyl glycidyl ether,
The prepreg according to claim 1, which is polypropylene glycol diglycidyl ether. 8. After dissolving the component [B] in the component [C],
The prepreg according to claim 1, which is impregnated with the composition prepared by mixing with the component [A]. 9. The prepreg according to claim 1, wherein the reinforcing material is carbon fiber, glass fiber, aromatic polyamide fiber alone or in combination thereof. 10. The following [A], [B], [C] and a curing agent for epoxy resin are contained as main components, and [A], [B],
The ratio of each component of [C] is 30 to 96% by weight, and 2 to 50, respectively.
A method for producing a prepreg, which comprises impregnating a reinforcing material with a resin composition in an amount of 2% by weight to 2% by weight by a hot melt method. [A] Epoxy resin [B] Thermoplastic resin [C] Epoxy resin other than the above-mentioned epoxy resin capable of dissolving the thermoplastic resin and / or reactive diluent having an epoxy group 11. A component (B) is dissolved in a part or all of the component (C) to prepare a premix (I), and then the premix (I) is mixed with the rest of the components (A) and (C) and the mixture. The method for producing a prepreg according to claim (10), characterized in that a resin composition is prepared by adding a curing agent for epoxy resin and the like. 12. A mixture (II) of the component (A) and the rest of the component (C) is added to the pre-mixture (I) in which the component (B) is dissolved in a part of the component (C), and then epoxy is further added. The method for producing a prepreg according to claim (10), wherein a resin composition is prepared by adding a curing agent for resin and the like.