JPH07149952A - Thermosetting resin composition, cured resin, prepaeg, and fiber-reinforced plastic - Google Patents

Abstract

PURPOSE:To obtain the composition which has good workability and can give a cured resin having high toughness as well as retaining high heat resistance and high modulus by mixing a specified thermosetting resin with a specified block copolymer and a specified rubber. CONSTITUTION:The composition comprises at least one thermosetting resin (A) selected from the group consisting of epoxy, cyanate and bismaleimide resins, a block copolymer (B) composed of an aromatic oligomer chain and an elastomer chain and at least one rubber (C) selected from the group consisting of silicone, butadiene, acrylic and nitrile rubbers. It is desirable that component A is an epoxy resin containing an aromatic amine curing agent or a maleimide resin containing a diallyl compound. It is desirable that component B has a number-average molecular weight in the range of 2000-10000 and is reactive with component A.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermosetting resin composition, a resin cured product, which is excellent in high toughness, high elongation, high elastic modulus, low internal stress property, high heat resistance and low water absorption, and The present invention relates to a prepreg and a fiber reinforced plastic using it as a matrix resin.

[0002]

2. Description of the Related Art Thermosetting resins have excellent mechanical properties,
Utilizing its chemical resistance, it is widely used in various industrial fields such as molding, lamination, and adhesives. In particular, thermosetting resins typified by epoxy resins are often used for fiber-reinforced composite materials that include reinforced fibers and matrix resins as essential components. On the other hand, however, the thermosetting resin has a drawback of being brittle, and thus has a problem that the cured product has poor impact resistance and a small elongation at break. Especially aircraft,
Poor impact resistance is a major problem when used for structural materials such as automobiles.

Various attempts have been made to improve the drawbacks of these thermosetting resins, especially the brittleness.

The toughness is improved by adding a rubber-like polymer having a terminal functional group (for example, a carboxyl group-terminated butadiene / acrylonitrile rubber) to an epoxy resin or a phenol resin. However, it has a drawback that the elastic modulus (particularly, the elastic modulus at high temperature) is greatly reduced.

In Japanese Patent Laid-Open No. 2-160859, a study is being made to add fine particles such as partially crosslinked butadiene acrylonitrile rubber to an epoxy resin. However, the effect of increasing the toughness of the epoxy resin having high heat resistance is still insufficient, and it is considered that the amount of rubber particles added increases and the elastic modulus decreases in order to obtain a large effect of improving the toughness.

US Pat. No. 4,656,208, JP-A-61
-228016, a polysulfone oligomer having an epoxy-reactive functional group at its end is considered to be added to an epoxy resin composition. It is stated that the cured resin has a microphase-separated structure (reverse sea island structure), polysulfone is present in a high concentration in the continuous phase, and has good heat resistance and high toughness. A similar study was presented by JE McGrath and others at the 31st SAMPE SYMPOSIUM page 580 (1986). The resin toughness increases as the molecular weight of polysulfone increases and the amount of polysulfone increases, but the drawback is that the viscosity of the system increases and the workability decreases. Also, because of the use of high-viscosity resin, the tackiness of the prepreg combined with the reinforcing fiber,
Drapability is reduced.

European Patent Publication No. 0311349 also examines addition of an amine-terminated polyallylsulfone to an epoxy resin composition. The structure varies depending on the skeleton structure of polyallyl sulfone, that is, the polyallyl sulfone phase and the epoxy resin phase are separated and both phases are continuous structure, and the continuous phase is polyallyl sulfone and the island phase is epoxy phase. However, the toughness is highest when both the polyallylsulfone phase and the epoxy resin phase have a continuous structure. The resin toughness increases as the molecular weight of polysulfone increases and the amount of polysulfone increases, but it is considered that the viscosity of the system increases and workability is greatly reduced. Also, because a high viscosity resin is used,
The tackiness and drapeability of the prepreg combined with the reinforcing fiber are deteriorated.

Japanese Unexamined Patent Publication (Kokai) No. 63-170411 discloses a composition in which an amine-terminated polysulfone oligomer is added to an epoxy resin composition, and a liquid rubber reactive with epoxy is further added. After curing, there is a disperse phase containing epoxy as a main component in the continuous phase containing polysulfone as a main component, and a micro phase separation structure containing a rubber phase is formed in the epoxy dispersed phase to form a high toughness resin. It is supposed to be. However, this method is considered to lower the elastic modulus and heat resistance of the cured resin because the liquid rubber is used by dissolving it in the epoxy component. In addition, when a large amount of polysulfone is added for higher toughness, the workability is significantly reduced. Moreover, since the high-viscosity resin is used, the tackiness and drapeability of the prepreg combined with the reinforcing fiber are deteriorated.

The present inventors also disclosed in Japanese Patent Laid-Open No. 2-305860 that the toughness can be improved by adding an amine-terminated polyimide-siloxane block copolymer to an epoxy resin. Although the viscosity increase with the addition of the modifier is relatively small, there is room for improvement in workability when a large amount of the modifier is added for higher toughness.

[0010]

The conventional techniques for improving the toughness as described above have their respective drawbacks such as a decrease in elastic modulus, heat resistance and workability, and the toughness improving effect. Is insufficient. That is, obtaining a cured resin having high toughness while maintaining good workability as a resin composition, high heat resistance as a cured product, and high elastic modulus is an important issue to be solved.

The present invention provides a thermosetting resin composition having these various physical properties, a cured product, a prepreg excellent in tackiness and drape using the cured product as a matrix resin, and high toughness and high heat resistance. It is an object to provide fiber reinforced plastic.

[0012]

In order to achieve the above object, the thermosetting resin composition of the present invention has the following constitution.
That is, it is a thermosetting resin composition characterized by comprising the following constituent elements [A], [B], and [C].

[A]: One or more thermosetting resins selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [B]: Block copolymer consisting of aromatic oligomer chain and elastomer chain [C] ]: One or more rubbers selected from the group consisting of silicone rubber, butadiene rubber, acrylic rubber, and nitrile rubber Further, the cured resin product of the present invention has the following constitution. That is, the phases having the following components [D], [E], and [F] as the main components are separated from each other, and the phase having the components [F] as the main component has [E] as the main component. The resin cured product is characterized by being contained in and existing in the phase.

[D]: at least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [E]: thermoplastic resin [F]: elastomer The prepreg of the present invention is as follows. Have a configuration. That is, it is a prepreg composed of the thermosetting resin composition and reinforcing fibers.

The fiber-reinforced plastic of the present invention has the following constitution. That is, it is a fiber-reinforced plastic comprising the resin cured product and reinforcing fibers.

The present invention will be described in detail below for each component.

(Description of Component [A]) In the present invention, the component [A] is at least one thermosetting resin selected from the group consisting of epoxy resins, cyanate resins and bismaleimide resins.

As the thermosetting resin particularly suitable for the present invention, an epoxy resin is first mentioned. The epoxy resin is a resin having an average of two or more epoxy groups per molecule. In particular, epoxy resins having an amine, a phenol, or a compound having a carbon-carbon double bond as a precursor are preferable. Specifically, as an epoxy resin using amines as a precursor, tetraglycidyldiaminodiphenylmethane,
Triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, various isomers of triglycidylaminocresol, and epoxy resins having phenols as precursors, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S Examples of the type epoxy resin, the phenol novolac type epoxy resin, the cresol novolac type epoxy resin, the resorcinol type epoxy resin, and the epoxy resin having a compound having a carbon-carbon double bond as a precursor include an alicyclic epoxy resin. Brominated epoxy resins obtained by bromizing these epoxy resins are also used. . These epoxy resins may be used as a mixture of two or more kinds, and may contain a monoepoxy compound.

The epoxy resin is preferably used in combination with a curing agent. As the curing agent, any compound having an active group capable of reacting with an epoxy group can be used. A compound having an amino group, an acid anhydride group, an azido group or a hydroxyl group is preferable.

Specific examples include dicyandiamide, various isomers of diaminodiphenyl sulfone, aminobenzoic acid esters, various acid anhydrides, phenol novolac resins, and cresol novolac resins. Dicyandiamide is preferred because it is excellent in storage stability of prepreg. When an aromatic diamine is used as a curing agent, an epoxy resin cured product having good heat resistance can be obtained. In particular, various isomers of diaminodiphenyl sulfone are most suitable for the present invention because they give a cured product having good heat resistance. Aminobenzoic acid esters include trimethylene glycol di-p.
-Aminobenzoate and neopentyl glycol di-p
-Aminobenzoate is preferably used, and although it is inferior in heat resistance to diaminodiphenyl sulfone, it is excellent in tensile elongation, so it is selected and used according to the application.
When an acid anhydride represented by methylhexahydrophthalic anhydride is used as a curing agent, a cured product with high heat resistance is obtained,
An epoxy resin composition having a low viscosity and excellent workability can be obtained. It is preferable to use a phenol novolac resin or a cresol novolac resin as a curing agent because an ether bond having excellent hydrolysis resistance is introduced into the molecular chain to improve the moisture resistance of the cured product.

In the present invention, maleimide resin is also preferable as the constituent [A]. Maleimide resin is a compound containing an average of two or more maleimide groups per molecule, and has the general formula

[Chemical 1] (In the formula, X is an alkylene group, a cycloalkylene group, a divalent hydrocarbon group such as a monocyclic or polycyclic arylene group, or —CH ₂ —, —CO—, —SO ₂ —, —O.
_{-, - C (CH 3)} 2 -, - those and represented by CONH- such divalent 2 joined by atomic monovalent hydrocarbon group), the general formula

[Chemical 2] (In the formula, n is a number from 1 to 4)

[Chemical 3] (In the formula, n is a number from 1 to 4) A maleimide compound obtained by reacting a mixed polyamine and maleic anhydride.

Examples of this type of maleimide compound include N, N'-phenylene bismaleimide, N, N'-hexamethylene bismaleimide, N, N'-methylene-di-p-phenylene bismaleimide, N, N '-Oxy-di-p-phenylene bismaleimide, N, N'-4,4'-benzophenone bismaleimide, N, N'-diphenylsulfone bismaleimide,
N, N '-(3,3'-dimethyl) -methylene-di-p-phenylene bismaleimide, N, N'-4,4'-dicyclohexylmethane bismaleimide, N, N'-m (or p)- Xylylene-bismaleimide, N, N '-(3,3'-diethyl) -methylene-di-p-
Phenylene bismaleimide, N, N'-metatorylene-di-
Examples thereof include maleimide and bismaleimide of bis (aminophenoxy) benzene, and reaction products of mixed polyamine, which is a reaction product of aniline and formalin, and maleic anhydride, but the present invention is not limited thereto. Also,
These maleimide compounds may be used as a mixture of two or more kinds, and may contain a monomaleimide compound such as N-allylmaleimide, N-propylmaleimide, N-hexylmaleimide or N-phenylmaleimide.

Maleimide resins are preferably used in combination with hardeners or reactive diluents. As the curing agent, any compound having an active group capable of reacting with the maleimide group can be used. A compound having an amino group, an alkenyl group represented by an allyl group, a benzocyclobutene group, an allyl nadic imide group, an isocyanate group, a cyanate group, or an epoxy group is preferable. For example,
Diaminodiphenylmethane is a typical example of the curing agent having an amino group, and examples of the curing agent having an alkenyl group include O, O′-diallylbisphenol A and bis (propenylphenoxy) sulfone.

A bismaleimide / triazine resin (BT resin) composed of the above-mentioned bismaleimide and a cyanate represented by the following general formula is also suitable as the thermosetting resin of the present invention.

[0025]

[Chemical 4] (In the formula, X is an alkylene group, a cycloalkylene group, a divalent hydrocarbon group such as a monocyclic or polycyclic arylene group, or —CH ₂ —, —CO—, —SO ₂ —, —O—, —
C (CH ₃ ) _2- , -CONH- and other divalent hydrocarbon groups bound by divalent atomic groups) Such a BT resin has a bismaleimide / cyanate weight ratio of 0/1.
It is used in the range of 00 to 70/30. The case of 0/100 corresponds to a cyanate resin, which is also suitable for the present invention. In this case, the cured product has a characteristic of low water absorption.

Further, respective combinations of these three kinds of thermosetting resins, such as epoxy resin and cyanate resin, cyanate resin and bismaleimide resin, are also suitable for the present invention.

(Description of Component [B]) The component [B] used in the present invention is a block copolymer of an aromatic oligomer chain and an elastomer chain.

The aromatic oligomer chain in the block copolymer of the aromatic oligomer chain and the elastomer chain used as the constituent element [B] is a divalent group such as a phenylene, diphenylene or naphthalene group linked by a divalent chain group. Those containing the aromatic group of are preferred. Rensamoto, for example oxy (-O-); a sulfonyl (-SO ₂ -); sulfide (-S-); oxyalkylene or oxyalkyleneoxy [-OR- or -ORO -, (R is preferably 1 to 3 Lower alkylene having 4 carbon atoms)]; lower alkylene or alkylidene [-R- or -R (R ₁ ) _y- , (R
And R ₁ is independently lower alkylene, y is 1 or 2
] ;; Ketone (-CO-) and the like. The aromatic oligomer chain has an imide skeleton [(-CO-) ₂ N-],
It is preferable to have an amide skeleton (-NHCO-) because it has both heat resistance and toughness. Those called aromatic polyethers, aromatic polyimides, aromatic polyamides, aromatic polysulfones, and aromatic polyketones (-CO-) correspond to these. It is preferable that 50% or more of all carbon atoms of the aromatic oligomer chain part have an aromatic structure, but the aromatic unit is chlorine, lower alkyl,
It may have a substituent such as phenyl.

The most preferable polyimide chain portion in the aromatic oligomer chain as the constituent element [B] may be any synthesis method known in the industry, but is typically tetracarboxylic dianhydride. It is synthesized by reacting with a diamino compound. For example, it is synthesized by the following combination of diamine and dianhydride.

Preferred examples of tetracarboxylic dianhydride are pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3',
4,4'-biphenyltetracarboxylic dianhydride, 3,
Aromatic tetracarboxylic dianhydrides such as 3 ', 4,4'-diphenyl ether tetracarboxylic dianhydride and 3,3', 4,4'-diphenylsulfone tetracarboxylic dianhydride, more preferably 3 , 3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4 '
There may be mentioned aromatic tetracarboxylic dianhydrides such as diphenyl ether tetracarboxylic dianhydride.

Preferred examples of diamino compounds are diaminodiphenylmethane, metaphenylenediamine, paraphenylenediamine, diaminodiphenyl ether, diaminodiphenylsulfone, diaminodiphenyl sulfide, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylketone, diaminodiphenylhexafluoropropane, Diaminodiphenylfluorene, bis (aminophenoxy) benzene, bis (aminophenoxy) diphenylsulfone, bis (aminophenoxy) diphenylpropane, bis (aminophenoxy) diphenylhexafluoropropane, fluorenediamine, dimethyl substitution product of diaminodiphenylmethane,
Aromatic diamino compounds such as tetramethyl-substituted diaminodiphenylmethane, diethyl-substituted diaminodiphenylmethane, tetraethyl-substituted diaminodiphenylmethane, and dimethyldiethyl-substituted diaminodiphenylmethane, more preferably bis (aminophenoxy)
Benzene, bis (aminophenoxy) diphenyl sulfone, bis (aminophenoxy) diphenylpropane,
Bis (aminophenoxy) diphenylhexafluoropropane, diaminodiphenylfluorene, fluorenediamine, dimethyl substitution product of diaminodiphenylmethane,
Aromatic diamino compounds such as tetramethyl-substituted diaminodiphenylmethane, diethyl-substituted diaminodiphenylmethane, tetraethyl-substituted diaminodiphenylmethane, and dimethyldiethyl-substituted diaminodiphenylmethane can be exemplified.

Typical examples of the elastomer chain portion in the constituent element [B] include a siloxane skeleton and an acrylonitrile-butadiene skeleton.

The siloxane skeleton is represented by the following formula.

[0034]

[Chemical 5] (In the formula, R ₂ is a divalent organic group, R ₃ is a monovalent organic group, R ₂ and R ₃ may be the same or different, and n is an integer of 1 to 20.) Particularly preferred Is dimethylsiloxane, but phenylsiloxane and its copolymers are also suitable.

Therefore, the constituent element [B] as a block copolymer composed of two kinds of chain parts is, for example, a polyimide-siloxane block copolymer, a polyamide-siloxane block copolymer, a polyether-acrylonitrile butadiene block copolymer. It becomes a polymer.

The constituent element [B] is appropriately selected and used so that it can be dissolved in the thermosetting resin composition as the constituent element [A].

Having a functional group capable of reacting with the constituent element [A] at the end of the constituent element [B] enhances the adhesiveness of the phase separation interface and contributes to the improvement of the toughness, and the solvent resistance inherent in the thermosetting resin. Is preferred for maintaining. Preferred functional groups are primary amines, secondary amines, hydroxyl groups, epoxy groups, carboxyl groups, acid anhydrides, maleimide groups and the like. Particularly, primary amines are preferable because they have excellent reactivity.

The molecular weight of component [B] is preferably in the range of about 2000 to 10,000 in terms of number average molecular weight. When the molecular weight is smaller than this, the effect of improving toughness is small, and
If the molecular weight is higher than this, the resin viscosity is remarkably increased and the workability is remarkably reduced. More preferably about 3000-
It is in the range of 5000.

The constituent element [B] is a block copolymer consisting of two kinds of chain parts of an aromatic oligomer chain and an elastomer chain, and the ratio of the chain lengths of each is such that the aromatic oligomer chain part is the elastomer chain part. Higher molecular weight is preferable because it improves heat resistance.

The preferred number average molecular weight ratio is 1 to 20 aromatic oligomer chain parts / elastomer chain parts. If it is smaller than this, the heat resistance may be significantly reduced, and if it is larger than this, the toughness improving effect is small. More preferably, it is in the range of 2-10.

The constituent element [B] preferably has a glass transition temperature (Tg) of 150 ° C. or higher in order to maintain the heat resistance of the cured resin. More preferable Tg range is 160 to 30.
The temperature is 0 ° C, and more preferably 170 to 250 ° C. Here, the glass transition temperature is a differential scanning calorimeter (D
SC) at 40 ° C / min. It is measured at the rate of temperature rise.

The amount of the constituent element [B] is 5 to 5 in the total resin composition.
30% by weight is preferred. If it is less than this, the toughness improving effect is small, and if it is more than this, the workability tends to decrease. It is more preferably 7 to 25% by weight, and further 10 to 20% by weight.

(Description of Component [C]) Component [C]
Is at least one rubber selected from the group consisting of silicone rubber, butadiene rubber, acrylic rubber, and nitrile rubber. As a method of selecting the constituent element [C], it is possible to increase the affinity between the constituent elements [B] and [C] by using a combination of the elastomer chain portion of the constituent element [B] and a rubber having a similar structure, It is preferable because it gives a cured product having a phase-separated structure suitable for improving toughness. For example, when a siloxane chain is used as the elastomer chain part of the constituent [B], silicone rubber is used as the constituent [C], and when acrylonitrile butadiene chain is used as the elastomer chain of the constituent [B], the constituent [C] is used. For example, acrylonitrile butadiene rubber is suitable.

Use of one or more solid rubbers selected from the above rubber group as the constituent element [C] makes the heat resistance and elastic modulus of the resin excellent as compared with the case of using liquid rubber. Is preferable because Further, the phase separation morphology of the cured product is less dependent on the curing conditions and the physical properties are more stable than when liquid rubber is added. Examples of the solid rubber include silicone rubber particles and crosslinked acrylonitrile butadiene rubber particles. It is also preferable to knead the solid nitrile rubber into the resin composed of the constituent elements [A] and [B].

It is preferable that the constituent element [C] has a functional group capable of reacting with the constituent element [B] or [A], because it contributes to the improvement of toughness and maintains the original solvent resistance of the thermosetting resin. Particularly preferred functional groups as such reactive functional groups are an epoxy group and an amino group.

Examples of commercially available silicone rubber particles include:
For example, E-601, E-602 and DY33-723 manufactured by Toray Dow Corning Silicone Co., Ltd. may be mentioned. The method for producing crosslinked acrylonitrile butadiene rubber particles is described in JP-A-2-160859.

When the constituent element [C] is used in combination with the constituent element [B], it is possible to obtain resin toughness which was difficult to achieve by adding only the constituent element [B]. In other words, it becomes possible to reduce the addition amount of the constituent element [B] required to obtain the same level of toughness. Therefore, workability is less likely to decrease due to an increase in resin viscosity. Therefore, a prepreg using this resin as a matrix resin is characterized by excellent tackiness and drapeability.

The amount of the constituent element [C] added is preferably 2 to 15% by weight based on the total resin composition. If it is less than this range, the effect of improving toughness is small, and if it is more than this range, heat resistance and workability may deteriorate. It is more preferably 3 to 10% by weight, and further 4 to 8% by weight.

It is preferable that the addition amount of the constituent element [C] is smaller than the addition amount of the constituent element [B] from the viewpoint of improving the toughness and maintaining the elastic modulus.

(Description of Cured Product) By curing the above resin composition, the following constituent elements [D], [E],
Thermosetting, in which the phase containing [F] as the main component is separated and the phase containing the component [F] as the main component is included in the phase containing [E] as the main component A resin cured product is obtained.

[D]: at least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [E]: thermoplastic resin [F]: elastomer When the above resin composition is cured , The phase having the constituent [D] as the main component and the phase having the constituent [E] as the main component are microphase-separated. ] Is preferred to be localized in a phase containing as a main component. In particular, it is preferable that 70% or more of the total amount of the phase containing the constituent [F] as the main component be localized in the phase containing the constituent [E] as the main component because the toughness improving effect will be large. It is considered that this is because the plastic deformation ability originally possessed by the constituent element [E] is effectively extracted due to the existence of the phase having the constituent element [F] as a main component. It is possible to form such a phase-separated structure by making the material of the constituent element [F] higher in affinity with the constituent element [E] than the constituent element [D].

Further, as the phase separation form of the cured resin, it is preferable that at least the phase containing the constituent [E] as a main component has a three-dimensional continuous structure in order to improve the toughness. More preferably, the phase having the constituent [E] as a main component and the phase having [D] as a main component are continuous phases, respectively. Such a characteristic phase-separated structure can be stably obtained by adding the constituent element [B], which is a block copolymer composed of two chains having different structures, regardless of changes in curing conditions. Is.
It is preferable that the period of the phase-separated structure formed from the phase containing [D] as a main component and the phase containing [E] as a main component is about 0.01 to 10 microns, because the toughness improving effect is large. More preferably
It is about 0.1 to 3 microns.

Component [F] uses the same material as component [C] in the corresponding composition. That is, at least one selected from the group consisting of silicone rubber, butadiene rubber, acrylic rubber and nitrile rubber.
It is preferable that the phase is composed mainly of seed solid rubber.

The phase containing the constituent [F] as the main component is preferably localized in the phase containing the constituent [E] as the main constituent, and the dispersed particle size at that time is about 0.01 to 10. It is preferable that the particle size is micron because the effect of improving toughness is large. More preferably, it is about 0.1 to 3 microns.

The phase-separated structure of the cured resin product can be observed by a microscope by a conventional method. It can be observed with an optical microscope, but in some cases, it is preferable to stain with osmium tetroxide or the like and observe with an electron microscope. The existence of three different phases is clear, at least one phase forms a continuous structure, and it can be seen that the dispersed phase exists in the continuous phase. X
By using a microscope together with an analyzer such as a line microanalyzer, it is possible to identify and infer the constituent elements. Tg of the phase whose main component is the component [E] specified in this way
Is preferably 150 ° C. or higher. More preferred T
The range of g is 160 to 300 ° C, and more preferably 170 to 250 ° C.

The degree of distribution of the phase containing the constituent [F] as the main component into the phase containing the constituent [D] as the main component and the phase containing the constituent [E] as the main constituent is about 2000 times. Copy the above micrograph of magnification, cut out the part corresponding to the constituent element [G] existing in each phase, weigh it, or obtain the area by the method of measuring with an image analyzer and compare it. The average value measured at at least 5 points is used.

The present invention also includes components [A], [B],
A prepreg composed of the thermosetting resin composition of [C] and a reinforcing fiber is provided.

Further, high toughness composed of a resin cured product composed of constituent elements [D], [E] and [F] and a reinforcing fiber,
Provide high strength fiber reinforced plastic.

Reinforcing fibers are fibers having good heat resistance and tensile strength which are generally used as advanced composite materials. Examples of the reinforcing fiber include carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, tungsten carbide fiber, and glass fiber. Among these, carbon fibers and graphite fibers, which have good specific strength and specific elastic modulus and are recognized to make a great contribution to weight reduction, are more preferable for the present invention. It is possible to use all kinds of carbon fibers and graphite fibers depending on the application, but the tensile strength is 450 kgf / mm.
^2. High strength and high elongation carbon fiber with tensile elongation of 1.7% or more is most suitable. Carbon fibers and graphite fibers may be used by mixing with other reinforcing fibers. The shape and arrangement of the reinforcing fibers are not limited, and the reinforcing fibers may be used in a single direction, a random direction, a sheet shape, a mat shape, a woven shape, or a braided shape. In addition, the arrangement in which the reinforcing fibers are aligned in a single direction is most suitable for applications that require high specific strength and high specific elastic modulus, but a cloth (fabric) arrangement that is easy to handle. Are also suitable for the present invention.

The prepreg of the present invention having the above-mentioned resin as a matrix has a characteristic that it has good tackiness and drapability because of its low resin viscosity. Further, it has an advantage in the manufacturing process that it is easy to coat the resin and impregnate the reinforcing fiber strand during the manufacturing of the prepreg.

A fiber-reinforced plastic composed of a cured product of the constituent elements [D], [E] and [F] and a reinforcing fiber reflects the high toughness of the matrix resin and has excellent toughness and impact resistance. . Laminates obtained by laminating and curing prepregs have excellent interlaminar toughness in the peeling mode while maintaining high interlaminar shear strength, compressive strength, and heat resistance. It has a feature that the plate edge peel strength (EDS) is extremely high.

[0062]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 Part A: Synthesis of Reactive Polyimide Siloxane Block Copolymer Oligomer In a 3000 ml separable flask equipped with a nitrogen inlet, a thermometer, a stirrer and a dehydration trap, under nitrogen displacement. 218 g (0.75 mol) of 1,3-bis (3-aminophenoxy)
Benzene (APB), 33 g (0.094 mol) of 9,9'-bis (4-
Aminophenyl) fluorene (FDA), 122g (0.094mo
l) NH ₂ equivalent 650 amino-terminated dimethyl siloxane (BY-16-853 manufactured by Toray Dow Corning Silicone)
It was dissolved with stirring in 2000 ml of N-methyl-2-pyrrolidone (NMP). There, solid diphenylsulfone tetracarboxylic dianhydride (Rikacide DSD manufactured by Shin Nippon Rika Co., Ltd.)
305 g (0.85 mol) of A) was added little by little, and the mixture was stirred at room temperature for 3 hours, then heated to 120 ° C. and stirred for 2 hours. The temperature of the flask was returned to room temperature, 50 ml of triethylamine and 50 ml of toluene were added, the temperature was raised again, and azeotropic dehydration was performed at 160 ° C. to obtain about 30 ml of water. After cooling the reaction mixture, double the volume of NMP
Diluted with and slowly poured into 20 l of acetone to precipitate the amine-terminated polyimidesiloxane block copolymer oligomer as a solid product.

Then, the precipitate was vacuum dried at 200 ° C. The number average molecular weight (Mn) of this oligomer was 5100 in terms of polystyrene when measured by gel permeation chromatography (GPC) using a dimethylformamide (DMF) solvent. The glass transition point was 189 ° C. according to a differential thermal analyzer (DSC). Further, the introduction of the siloxane skeleton and the presence of amine terminals could be confirmed from the NMR spectrum and IR spectrum.

Part B: Resin preparation and measurement of resin physical properties In a beaker, 25 parts of the polyimidesiloxane block copolymer oligomer of Part A above and 40 parts of phenol novolac type epoxy resin (Epicote 154, manufactured by Yuka Shell Epoxy Co., Ltd.), 30 parts of a bisphenol A type epoxy resin (Yukaka Shell Epoxy Co., Ltd., Epicoat 825) and 30 parts of a bisphenol F type epoxy resin (Dainippon Ink & Co., Inc., Epicron 830) were weighed. The oligomer was dissolved in the epoxy resin by heating it at 120 ° C. for 2 hours. Then, at 60 ° C., silicon rubber fine particles (Toray Dow Corning Silicone Co., Ltd., E
-601) was added to 12 parts, and the mixture was stirred and mixed for 30 minutes. Further, 34 parts of 4,4'-diaminodiphenyl sulfone (Sumicure S, manufactured by Sumitomo Chemical Co., Ltd.) was added, and mixed and dissolved at 140 ° C for 10 minutes.

A vacuum pump was connected to the container for vacuum defoaming, and the contents were preheated to 120 ° C. and subjected to a mold release treatment (the size of the void was 120 × 120 × 3 mm).
). 130 ° C in the oven, 2 hours +180
A resin cured plate having a thickness of 3 mm was prepared by curing reaction at ℃ for 2 hours.

The Tg of the obtained cured resin was 201 ° C. When the sample was cut out from this and the fracture strain energy release rate G _IC was measured, it was 1050 J / m ² , and the flexural modulus E was 340 kg / mm ² . Here, the flexural modulus was measured according to ASTM D790. Also,
G _IC = G _IC = from stress intensity factor K _IC obtained by ASTM E399-83, Poisson's ratio γ, flexural modulus E
Calculated according to K _IC ² (1-γ ² ) / E.

When the polished surface of the cured resin was stained with osmic acid and the backscattered electron image was observed with a scanning electron microscope, a microphase-separated structure in which the two phases together form a continuous phase was observed, and one phase was in the visual field. 82% of all silicone rubber particles
Was localized. Elemental analysis of the same field of view with an X-ray microanalyzer showed that silicon element was densely distributed in the continuous phase on the side where the silicon rubber particles were localized, and it was found that the polyimide siloxane block copolymer oligomer was the main phase. It could be confirmed.

Part C: Preparation of prepreg and composite material and measurement of physical properties A unidirectional prepreg having the following constitution was produced. First, the following thermosetting resin composition was prepared in a kneader in advance and thinly applied on release paper to prepare a resin film.
The viscosity of the resin used here was measured with a dynamic viscoelasticity measuring apparatus RDA-2 manufactured by Rheometric Co. and found to be 610 poise at 80 ° C.

A prepreg was prepared by sandwiching the following unidirectional carbon fiber as a reinforcing fiber from above and below with a resin film and impregnating the resin to obtain a prepreg having a carbon fiber areal weight of 192 g / m ² and a resin weight fraction of 36%. This prepreg was excellent in tackiness and drapeability.

Reinforcing fiber: carbon fiber T800H-12K-
40B (manufactured by Toray Industries, Inc.) Thermosetting resin composition: Resin consisting of the following composition: Phenol novolac type epoxy resin (Epicoat 154, manufactured by Yuka Shell Epoxy Co., Ltd.) 40 parts by weight Bisphenol A Type Epoxy Resin (Yukaka Shell Epoxy Co., Ltd., Epicoat 825) ・ ・ ・ 30 parts by weight Bisphenol F type epoxy resin (Dainippon Ink & Co., Inc., Epicron 830) ・ ・ ・ ・ ・ 30 parts Quantitative Part Polyimide siloxane block copolymer oligomer described in Part A ... 25 parts by weight Silicon rubber fine particles (E-601 manufactured by Toray Dow Corning Silicone Co., Ltd.) 12 parts by weight 4,4 '-Diaminodiphenylsulfone (Sumicure S, manufactured by Sumitomo Chemical Co., Ltd.) 34 parts by weight 20 layers of this prepreg are laminated in one direction. When the interlaminar toughness of the composite was measured, the peeling mode toughness G _IC was 790 J / m ² (double cantilever beam method).

(± 25 / ± 25/90) _S configuration 10
A tensile test was performed using a cured plate that was laminated in layers and molded, and the strength at which plate edge peeling occurred, that is, EDS, was determined to be 63.5 ksi.

Using a cured plate obtained by laminating 24 layers of prepreg in one direction and molding, the compressive interlaminar shear strength (CILS) was determined from the same test piece as in Example 1 and was found to be 11.7 ksi.

A cured plate obtained by laminating 6 layers of prepregs in one direction and molding was used for 82 hours after absorbing water in warm water (72 ° C.) for 2 weeks.
The compressive strength at ℃ was determined according to SACMA SRS1-88, it was 196 ksi.

[Comparative Example 1] The same resin as in Example 1 was used as the matrix resin except that the silicone rubber particles were omitted.
The same procedure as in Example 1 was repeated.

The breaking strain energy release rate G _IC of the obtained cured resin was measured and found to be 370 J / m ² , which was significantly inferior to the examples. Flexural modulus E is 340 kg / mm ²
Met.

The toughness G _{IC in the} peeling mode of a laminate of 20 layers of prepregs in one direction was 410 J / m ² (double cantilever beam method), which was inferior to the examples.

(± 25 / ± 25/90) _S 10
A tensile test was performed using a cured plate laminated in layers and molded, and the EDS was determined to be 46.8 ksi, which was inferior to the examples. [Comparative Example 2] The same thing as in Example 1 was used as the matrix resin except that the addition amount of the polyimidesiloxane block copolymer oligomer was increased to 50 parts by weight and the silicone rubber particles were removed.
The same procedure as in Example 1 was repeated. The resin viscosity was higher than that of Example 1 and was 9600 poise at 80 ° C.
Met.

The breaking strain energy release rate G _IC of the obtained cured resin was measured and found to be 710 J / m ² . The flexural modulus E was 330 kg / mm ² .

The prepared prepreg reflects the high viscosity of the resin used, has poor tack, and has a drapability as in Example 1.
Was significantly inferior to.

The peeling mode toughness G _IC of 20 layers of prepregs laminated in one direction was 570 J / m ² (double cantilever beam method), which was inferior to the examples.

(± 25 / ± 25/90) 10 with _S configuration
A tensile test was performed using a cured plate laminated in layers and molded, and the EDS was determined to be 53.8 ksi, which was inferior to the examples. [Comparative Example 3] The same procedure as in Example 1 was repeated using the same matrix resin as in Example 1 except that the polyimidesiloxane block copolymer oligomer was omitted.

The breaking strain energy release rate G _IC of the obtained cured resin was measured and found to be 150 J / m ² , which was significantly inferior to the examples. Flexural modulus E is 350 kg / mm ²
Met.

The toughness G _{IC in the} peeling mode of the 20 layers of prepregs laminated in one direction was 190 J / m ² (double cantilever beam method), which was significantly inferior to the examples.

(± 25 / ± 25/90) 10 in _S configuration
A tensile test was performed using a cured plate laminated in layers and molded, and EDS was found to be 27.9 ksi, which was significantly inferior to the examples.

[0086]

Industrial Applicability According to the present invention, it is possible to provide a resin composition which is a cured resin having high toughness while maintaining good workability, high heat resistance of a cured product, and high elastic modulus. In addition, it is possible to provide a prepreg excellent in tackiness and drape, which uses this as a matrix resin, and a fiber reinforced plastic having high toughness, high elastic modulus, and high heat resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 79/00 LQZ 83/04 LRY

Claims (11)

[Claims] 1. A thermosetting resin composition comprising the following constituent elements [A], [B] and [C]. [A]: at least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [B]: block copolymer consisting of aromatic oligomer chain and elastomer chain [C]: silicone At least one rubber selected from the group consisting of rubber, butadiene rubber, acrylic rubber and nitrile rubber 2. The thermosetting resin composition according to claim 1, wherein the constituent element [A] is an epoxy resin containing an aromatic amine curing agent. 3. The thermosetting resin composition according to claim 1, wherein the constituent element [A] is a maleimide resin containing a diallyl compound. 4. The thermosetting resin composition according to claim 1, wherein the constituent element [B] is reactive with the constituent element [A]. 5. The component [B] has a number average molecular weight of 2000.
The thermosetting resin composition according to claim 1, wherein the thermosetting resin composition is in the range of 10,000 to 10,000. 6. A prepreg comprising the thermosetting resin composition according to claim 1 and a reinforcing fiber. 7. The phases having the following constituents [D], [E], and [F] as main components are separated from each other, and the phase having the constituent [F] as a main component is [E]. A cured resin, which is contained in a phase as a main component and is present. [D]: at least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [E]: thermoplastic resin [F]: elastomer 8. 70% of a phase whose main component is [F]
The resin cured product according to claim 7, wherein the above is present in a phase containing [E] as a main component. 9. The cured resin product according to claim 7, wherein the phase containing the constituent [D] as a main component and the phase containing the constituent [E] as a main component are continuous phases. 10. The component [F] is an elastomer composed of one or more rubbers selected from the group consisting of silicone rubber, butadiene rubber, acrylic rubber and nitrile rubber. Resin cured product. 11. A fiber reinforced plastic comprising the thermosetting resin cured product according to claim 7 and reinforcing fibers.