JPS63221139A - Prepreg and its production - Google Patents

Abstract

PURPOSE:To obtain a prepreg for composite materials excellent in heat resistance, impact resistance and toughness, by impregnating a reinforcement with a resin composition comprising three specified components by a hot melt process. CONSTITUTION:A resin composition (B) is obtained by mixing 30-96wt.% thermosetting resin (a) based on a polyfunctional maleimide such as a polymaleimide compound of formula I (wherein R1 is a bi- to penta-valent aromatic or aliphatic organic group, X1-2 are each H, a halogen or an alkyl, and m is 2-5) and a polyfunctional cyanic ester of formula II (wherein R2 is a polyvalent aromatic organic group and n is 1-10) with 2-50wt.% thermoplastic resin (b) such as polycarbonate, poly(ether) sulfone or polyether imide, preferably, of a particle diameter <=400mu and a glass transition temperature >=100 deg.C and 2-49wt.% epoxy resin such as a glycidyl ester type of a viscosity <=150p (at 25 deg.C) and/or epoxy group-containing reactive diluent. A reinforcement (A) comprising at least one member selected from among carbon, glass and aromatic polyamide fiber is impregnated with component B by a hot melt process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is a prepreg for a composite material that is heat resistant and has excellent impact resistance, and a method for producing the same.

More specifically, high-strength carbon fiber or the like is used as a reinforcing material, and the excellent mechanical and thermal properties of thermosetting resin are combined with thermal 'III'.
The present invention relates to a prepreg that can be suitably used for composite materials that provide a molded product that has the excellent toughness of a plastic resin, and a method for producing the prepreg.

(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, etc., due to their high specific strength and specific stiffness. It's coming.

Even in epoxy resin prepregs, the combination of aromatic glycidylamine type epoxy resin and diaminodiphenylsulfone curing agent system as the matrix resin allows
Excellent heat resistance, mechanical properties, dimensional stability, chemical resistance,
We have provided composite materials that provide weather resistance.

Furthermore, in order to increase heat resistance, as a matrix resin,
Bismaleimide resins and the like are being studied and are being applied to aircraft-substructure materials.

Composite materials made from such thermosetting resin prepregs have been recognized to exhibit good performance;
On the other hand, it has been pointed out that the matrix resin has low elongation and is brittle, resulting in poor toughness and impact resistance of composite materials, and improvements have been sought. In particular, when these composite materials are used for aviation structural materials, they may be exposed to external shocks such as pebbles being thrown up during takeoff and landing, and tools falling during maintenance. It is necessary to improve the impact resistance without sacrificing the material, but this has become an important issue that is difficult to solve.

When trying to improve the impact resistance of prepregs, it goes without saying that it is important to improve the elongation of reinforcing materials such as carbon fibers, but it is also important to increase the toughness of the matrix resin used in prepregs. This has been pointed out, and many attempts have been made to improve the matrix resin.

As means for improving the toughness of matrix resins for prepregs, methods of mixing a rubber component with a thermosetting resin, a method of mixing a high molecular weight component, a method of mixing a filler, etc. have been considered.

However, in the case of a method of mixing a rubber component with a thermosetting resin, the toughness and impact resistance of the molded product are improved, but
Since the heat resistance and mechanical properties are lowered, the blending layer is regulated, and depending on the application, the blending amount remains low, and a sufficient modifying effect is not provided. In addition, in the case of a method of mixing a high molecular weight component with a thermosetting resin, for example, when a high molecular weight thermosetting resin such as phenoxy resin is added, the amount of blending is regulated from the viewpoint of heat resistance, similar to the rubber component. , the improvement effect is insufficient.

As a method of mixing thermoplastic resin with thermosetting resin,
Previously, the thermoplastic resin was added to the thermosetting resin in the form of a fine powder, or the thermoplastic resin was dissolved in a solvent and then this liquid was mixed with the thermosetting resin. When loaded, the composition tended to be non-uniform and the mechanical properties deteriorated. Furthermore, when mixing using a solvent, there are disadvantages such as problems in removing the solvent after mixing, the preparation method being troublesome, and residual solvent used to reduce heat resistance. If a large amount of filler is mixed, the tackiness of the prepreg will decrease, making it extremely difficult to handle, or the functional groups in the filler will act on the epoxy resin, worsening the storage stability of the prepreg. It had drawbacks.

Therefore, the matrix resin of prepreg for fiber-reinforced composite materials has conventionally contained small amounts of rubber components, high molecular weight components, fillers, etc., but although the conventional method does not reduce the heat resistance, it does not reduce the impact resistance. The improvement effect was poor.

(Object of the Invention) An object of the present invention is to provide a prepreg and a method for producing the same that overcome the above-mentioned problems and provide a composite material with excellent mechanical properties such as heat resistance, toughness, and impact strength. It is in. That is, we provide a prepreg impregnated with a uniform thermosetting resin/thermoplastic resin mixed composition as a matrix resin, which can be suitably used for hot melt type fiber reinforced composite materials that combine the advantages of both resins, and a method for producing the prepreg. It's about doing.

[Structure and effects of the invention]

[A]
(B) It is impregnated with a resin composition containing [C] as the main component, and the ratio of each component of [A], (B), and [C] is 30 to 96%, 2%, respectively. ~50% by weight, 2
It is a prepreg characterized by having a weight content of ~49%.

[A] Thermosetting resin mainly composed of polyfunctional maleimides and polyfunctional cyanate esters (B) Thermoplastic resin [C] Epoxy resin and/or epoxy group having the ability to dissolve the above thermoplastic resin The present invention also provides a reactive diluent having the following [
The main components are A](B)[C], and n [A]CB)[C
] The ratio of each component is 30 to 96% and 2 to 5%, respectively.
0 weight% is a prepreg manufacturing method characterized by impregnating a resin composition of 2 to 491 fit% by a hot melt method.

[A] Thermosetting resin mainly composed of polyfunctional maleimides and polyfunctional cyanate esters (B) Thermoplastic resin [C] Epoxy resin and/or epoxy resin having the ability to dissolve the above thermoplastic resin Resin composition (matrix resin composition) in the present invention having a reactive diluent
Then, component (8) dissolves the [C] component, and the [C]
Because the component acts as a mediator between the [A] component and the (B) component,
The preparation method is easy, and a uniform matrix composition of thermosetting resin component/thermoplastic resin component for hot melt use can be provided without using a solvent. Therefore, the prepreg obtained therefrom has excellent mechanical properties of the thermosetting resin component,
A molded article with improved toughness and accompanying impact resistance can be provided without impairing heat resistance.

As the reinforcing material in the present invention, carbon*mrta, glass fiber, aromatic polyamide fiber, etc. having an elongation of 1.3% or more are preferable. Glass fibers and aromatic polyamide fibers usually have an elongation of 2.5% or more. When carbon fibers with an elongation of less than 1.3% are used, the impact properties of the composite material tend to be somewhat insufficient.

Is it possible to tensile to improve the mechanical properties of composite materials? A
400kof/+u' u, elastic modulus 30T/mt
a' tl) This can be done when medium elongation high strength carbon fiber is used.

In the resin composition suitable for the present invention, the thermosetting resin component [A] mainly contains polyfunctional maleimides and polyfunctional Nisder cyanates. includes a polymaleimide compound represented by the following general formula (1) having two or more maleimide groups in the molecule, and a prepolymer derived from the polymaleimide compound.

(In the formula, R1 is a divalent to pentavalent aromatic or aliphatic organic group, XI and X2 are hydrogen, halogen, or an alkyl group, and m represents an integer of 2 to 5.) Furthermore, polyimide Modified prepolymers obtained by adding amines to compounds are also available.
It is included in component A], and these may be used alone or in combination. The above prepolymer is obtained by heating a polymaleimide compound in the presence or absence of a catalyst, optionally with a compound having one or more 7-mino groups in the molecule, so as not to result in gelation. It is a product.

Polyfunctional cyanate esters include polycyanate ester compounds represented by the following general formula (2) having two or more cyanate ester groups in the molecule, and prepolymers derived from this polycyanate ester compound. do.

R2-(-〇-C=N>n・・・・・・・・・・・・(
2) (In the formula, R2 is a polyvalent aromatic organic group, the cyanate ester group is directly bonded to the aromatic ring of R2, and n
represents an integer from 2 to 10. ) Component [A] may contain 5 to 50% by weight of an epoxy resin, and the epoxy resin is not particularly limited.

As a curing accelerator for the resin composition, imidazole compounds, urea compounds, such as 3(3,4-dichlorophenyl)
-1,i-dimethylurea, etc.), organometallic salts (eg, Go(II) acetylacetonate, etc.), peroxides such as dicumyl peroxide, etc. can also be used.

Component (B) thermoplastic resins include polycarbonate, polyetherketone, polysulfone, polyethersulfone, polyetherimide, aromatic polyester, etc. Among these, polycarbonate, polysulfone, polyethersulfone, polyneedleimide, etc. , aromatic polyester is preferable from the viewpoint of homogeneous mixability.

These thermoplastic resins can be used in combination of 2 or more PJ.

These thermoplastic resin (B) components have a particle size of 400 μm.
From the viewpoint of resin preparation, it is particularly preferable that the resin be in the form of a powder with a diameter of 100 μm or less. Further, from the viewpoint of heat resistance, those having a glass transition temperature of 100° C. or higher are preferable.

Among component [C] in the present invention, as the epoxy resin having thermoplastic resin dissolving ability, glycidyl ester type epoxy resin (for example, Epicoat manufactured by Shell Chemical Co., Ltd.
191), glycidylamine type epoxy resins (eg, GOT, GAN manufactured by Nippon Kayaku Co., Ltd.), etc.

[C] Among the reactive diluents capable of dissolving thermoplastic resins, the jepoxy compounds include diglycidyl ether, butanediol glycidyl ether, 2-glycidyl phenyl glycidyl ether, resorcinol diglycidyl ether, and hexanediol diglycidyl ether. , polypropylene glycol diglycidyl ether, etc., and monoepoxy compounds include alkylphenol glycidyl ether, phenyl glycidyl ether, butyl glycidyl ether, cresol glycidyl ether, styrene oxide, etc.

These [C] components can be used in combination of two or more. Further, it is preferable to use one having a viscosity of 150 poise or less at 25°C. This is to avoid generally increasing the viscosity of the resin when the thermoplastic resin is melted, and also to avoid poor handling of the 1q prepreg. However, if the viscosity of component [A] is low or the amount of thermoplastic resin to be mixed is small and there is no problem in handling, such consideration is not necessary.

The combination of component (B) and component [C] means that component [C] is (
B) It is necessary to have a relationship that dissolves the components, and if this relationship does not exist, the resin composition will not be uniform,
The purpose of the present invention cannot be achieved.

Examples of combinations of component [C] that are compatible with component (B) are as follows.

Table 1 (Note) PES: Polyether sulfone (ICI V[CT
REX) PEI: Polyneedlelimide (Ultsum manufactured by EPL) 1) Su: Polysulfone PC: Polycarbonate GΔN Nidiglycidylaniline GOT Nidiglycidyl toluidine PGE: Phenyl glycidyl ether BGE Nibutyl glycidyl ether 1-IGE: Hexanediol diglycidyl Aete PP
G: Polypropylene glycol diglycidyl ether Epicoat 191 nigericidyl ester type epoxy resin manufactured by Shell Chemical Co., Ltd. In order to simplify the preparation method in the [A] component/[B] component/[C] acid component combination, (B ) ingredients in advance [C]
It is preferable to adopt a method of dissolving the component and then adding component [A].

The blending ratio of [A] component/[B] component/[C] acid component is [A]
, (B) and [C] are respectively 30-96% by weight and 2-96% by weight.
501fi amount%, 2 to 49% by weight.

Particularly preferred is 10 to 300 to 30% by weight of component (B) and 5 to 30% by weight of component (B).

If the blending ratio of CB) component is more than 50% by weight, the melt viscosity becomes high, which makes roll mill mixing difficult, and also causes poor impregnation between fibers during prepreg production, making it difficult to obtain a good prepreg. . [C] The mixing interval of ingredients is 4
If the amount is more than 9%, the heat resistance of the composite material (η) will be extremely lowered and the mechanical properties will also be lowered, which is undesirable.

If component (B) and component [C] are each less than 2% by weight, the object of the present invention will not be achieved. The ratio of component (B)/component [C] is preferably 2 or less.

If the ratio is more than 2, the viscosity of the composition will be poor and the handling will be poor.
In the case of prepreg, the impregnating property between the fibers decreases and the tack is also low, which is not preferable. It also causes a decrease in mechanical properties. It is preferable that the blend m of the component [C] is kept to a minimum value so that the matrix resin composition has a uniform composition in relation to the blend M) of the component (B).

In addition to the above-mentioned essential components, the resin composition of the present invention includes a small amount of rubber components (e.g., carboxyl-terminated butadiene-acrylonitrile copolymer, nitrile rubber, etc.) that does not reduce heat resistance, and a prepreg. A filler (for example, silica powder), a flame retardant such as antimony trioxide, or a coloring agent may be added to the extent that the handleability 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 heated and kneaded, preferably under an inert gas atmosphere. The heating temperature at this time is lower than the curing start temperature of the epoxy resin. Or (B
Dissolve component [C] in component ), add component [A], etc., and knead. At this time, if component (B) is dissolved in part or all of component [C] and there are remaining components [A] and [C],
The remaining [C] component is added to the [A] component separately or in advance.
A] Adding and kneading after heating with pA is preferable in order to reduce the thermal history imparted to the resin composition and quickly obtain a uniform resin composition. In either case, the epoxy resin curing agent component is preferably added last and kneaded. Usually the temperature is 20 to 200°C, particularly preferably 50 to 15°C.
Prepare at a temperature of 0°C.

When preparing a prepreg by impregnating reinforcing fibers with the resin composition for prepreg of the present invention, the so-called hot melt method, which is already known, can be used.

The resin composition of the present invention is a resin composition in which each component is uniformly mixed because component [C] is present as a mediator between the thermosetting resin of component [A] and the thermoplastic resin of component (B). It is a resin composition suitable for prepregs with a rating of 7-11, which has the excellent heat resistance of a thermosetting resin and the toughness, impact strength, etc. of a thermoplastic resin, without the presence of residual solvent.

Additionally, due to solubility issues, when a homogeneous mixture of components ([3) and [C] is mixed with component [A], component (B) may precipitate as a layer of a certain size. However, even in that case, it goes without saying that the mixed state will be more uniform than when the [A] component and the (B) component are simply mixed.

Both the one-sided prepreg and the woven prepreg prepared by such operations are of good quality.

[Examples and comparative examples]

Examples 1 to 5 and Comparative Examples 1 to 5 A promoter was further added to a homogeneous mixture of components [A], (B), and [C] having the types and compounding ratios shown in Table 2 to obtain a resin composition for prepreg. Ta. A resin film is made from this composition using a film coater, and carbon! lH Besphite IM-500 (manufactured by Toho Rayon Co., Ltd., tensile strength 500 kQf/layer 12, elastic modulus 307
/IIlrm”), heated and impregnated with carbon mMq
A unidirectional pre-reg with a weight of 150 g/m 2 and a resin content of 34% by weight was obtained.

From this prepreg, a predetermined number of sheets of prepreg were cut and laminated, and test pieces were cut from the molded plates that were heated and hardened by autoclave molding, and the glass transition temperature, QO interlaminar shear strength, O0 compressive strength, 750in -1b / 1
The damage area and post-impact compressive strength after nlj impact were measured.

The results are shown in Table 2.

In addition, as a comparative example, (8) a system in which no component is added, (B)
Regarding the system without component [C], prepregs were produced 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
Although the thermal and mechanical properties are not much different compared to 750in.
-1b/in The damage area upon impact was small and the compressive strength after impact was high, making it clear that this is a composite material with excellent impact resistance.

Examples 6-7 Component CB) was mixed in advance with component [C] in the types and proportions shown in Table 2, and heated and mixed at 110°C for 1 hour with stirring to obtain a homogeneous mixture of components (B) and [C]. I got it. Furthermore, [A] component and accelerator component of the type and blending ratio shown in Table 2 were added, and roll mill mixing was performed at 80°C for 1 hour.
A b41Ff composition for prepreg was obtained. After that, prepregs were made in the same manner as in Examples 1 to 5. Example 1~
Molded plates were prepared in the same manner as in No. 5, and the composite properties were measured. As shown in Table 2, it was found that these were composite materials with excellent impact resistance.

Claims (11)

[Claims] (1) The following [A] [B] can be used as a reinforcing material using carbon fiber, glass fiber, or aromatic polyamide fiber alone or in combination.
It is impregnated with a resin composition containing [C] as the main component, and the ratio of each component of [A], [B], and [C] is 30
-96% by weight, 2-50% by weight, and 2-49% by weight. [A] Thermosetting resin mainly composed of polyfunctional maleimides and polyfunctional cyanate esters [B] Thermoplastic resin [C] Epoxy resin and/or epoxy group having the ability to dissolve the above thermoplastic resin reactive diluent with (2) Claims (1) in which the thermoplastic resin of component [B] is polycarbonate, polysulfone, polyethersulfone, polyetherimide, or aromatic polyester.
Prepreg described in ). (3) Claim (1) wherein the epoxy resin capable of dissolving thermoplastic resin, component [C], is a glycidyl ester type epoxy resin or a glycidyl amine type epoxy resin having a viscosity of 150 poise or less (temperature 25°C) or less. Prepreg as described. (4) The reactive diluent having an epoxy group as the [C] component is a diepoxy compound such as diglycidyl ether, butanediol glycidyl ether, 2-glycidyl phenyl glycidyl ether, resorcinol diglycidyl ether, hexanediol diglycidyl ether,
The prepreg according to claim (1), which contains polypropylene glycol diglycidyl ether, and the monoepoxy compounds include alkylphenol glycidyl ether, phenyl glycidyl ether, butyl glycidyl ether, cresol glycidyl ether, and styrene oxide. (5) The prepreg according to claim (1), wherein the ratio of [B] component/[C] component is 2 or less. (6) [B] The thermoplastic resin of the component is polysulfone, polyethersulfone, polyetherimide, [C
] A patent claim in which the component epoxy resin capable of dissolving a thermoplastic resin and/or a reactive diluent having an epoxy group is diglycidyl aniline, diglycidyl toluidine, phenyl glycidyl ether, butyl glycidyl ether, or polypropylene glycol diglycidyl ether. The prepreg described in scope (1). (7) The prepreg according to claim (1), which is impregnated with a composition prepared by dissolving component [B] in component [C] and then mixing it with component [A]. (8) The prepreg according to claim (1), wherein the reinforcing material is carbon fiber, glass fiber, or aromatic polyamide fiber alone or in combination. (9) The following [A] [B] may be used as a reinforcing material of carbon fiber, glass fiber, or aromatic polyamide fiber alone or in combination.
[C] is the main component, and the ratio of each component of [A], [B], and [C] is 30 to 96% by weight and 2 to 50% by weight, respectively.
A method for producing a prepreg, characterized by impregnating it with 2 to 49% by weight of a resin composition by a hot melt method. [A] Thermosetting resin mainly composed of polyfunctional maleimides and polyfunctional cyanate esters [B] Thermoplastic resin [C] Epoxy resin and/or epoxy group having the ability to dissolve the above thermoplastic resin reactive diluent with (10) Component [B] is dissolved in part or all of component [C] to form a premix (I), and then this premix (
A method for producing a prepreg according to claim (9), characterized in that a resin composition is prepared by adding the remainder of component [A] and component [C] to I). (11) A mixture (I) of component [A] and the remainder of component [C] is added to a premix (I) in which component [B] is dissolved in part or all of component [C] to form a resin composition. A method for producing a prepreg according to claim (9), characterized in that: