JPH07150042A - Resin composition, cured resin, prepreg and fiber-reinforced plastics - Google Patents

Abstract

PURPOSE:To obtain a prepreg excellent in tackiness and drapeability and a fiber-reinforced plastics having high toughness, modulus of elasticity and heat resistance together. CONSTITUTION:This resin composition comprises the following constituent elements [A], [B] and [C]: [A] at least one thermosetting resin selected from the group consisting of an epoxy resin, a cyanate resin and a bismaleimide resin, [B] a block copolymer composed of an aromatic oligomer and a siloxane oligomer and [C] silicone fine particles. This prepreg comprises the composition and reinforcing fiber. Furthermore, this cured resin is prepared by curing the composition and this fiber-reinforced plastics comprises the cured resin and the reinforcing fiber.

Description

Detailed Description of the Invention

[0001]

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

[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.

[0006] In US Pat. No. 4,656,208 and JP-A-61-228016, investigations have been made on adding a polysulfone oligomer having an epoxy-reactive functional group at the end 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 J. E. 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. Moreover, since the high-viscosity resin is used, the tackiness and drapeability of the prepreg combined with the reinforcing fiber are deteriorated.

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. Resin toughness increases as the molecular weight of polysulfone increases and the amount added increases,
It is considered that along with this, the viscosity of the system is increased and 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.

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, when a large amount of the modifier is added for higher toughness, the workability is still significantly reduced.

[0010]

As described above, the conventional methods for improving toughness have drawbacks such as a decrease in elastic modulus, heat resistance and workability, and moreover, a toughness improving effect. Is insufficient. That is, it is still an important subject to obtain 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.

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

[0012]

In order to solve the above problems, the resin composition of the present invention has the following constitution. That is, a resin composition comprising the following constituent elements [A], [B], and [C]. , [A]: at least one thermosetting resin selected from an epoxy resin, a cyanate resin, and a bismaleimide resin [B]: a block copolymer composed of an aromatic oligomer and a siloxane oligomer [C]: silicone fine particles The cured resin product of the present invention has the following constitution. That is, the phase having the following constituent [E] as the main component, the phase having [F] as the main component, and the phase consisting of [G] are separated from each other, and the phase consisting of the constituent [G] is [ F] is a resin cured product which is contained in a phase containing F as a main component.

[E]: at least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [F]: thermoplastic resin containing silicon [G]: silicone fine particles The prepreg has the following structure. That is, it is a prepreg composed of the 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.

(Explanation of Component [A]) The component used as the component [A] in the present invention is at least one curable resin selected from an epoxy resin, a cyanate resin and a bismaleimide resin.

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 2 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, tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-
As an epoxy resin containing m-aminophenol, various isomers of triglycidylaminocresol, and phenols as precursors, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol Examples of the novolac type epoxy resin, the resorcinol type epoxy resin, and the epoxy resin containing a compound having a carbon-carbon double bond as a precursor include alicyclic epoxy resins. Brominated epoxy resins obtained by brominating these epoxy resins are also used, but the present invention is not limited thereto. 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 thereof include, but are not limited to, 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. As the aminobenzoic acid esters, trimethylene glycol di-p-aminobenzoate and neopentyl glycol di-p-aminobenzoate are preferably used. Although they have poor heat resistance as compared with diaminodiphenyl sulfone, they have a tensile elongation. Because it excels in
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 having high heat resistance is obtained, and an epoxy resin composition having 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, a maleimide resin is also preferable as the constituent element [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] (Where n is a number from 1 to 4)

[Chemical 3] A maleimide compound obtained by reacting a mixed polyamine represented by the formula (n is a number of 1 to 4) with 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'-metatrylene-di-maleimide and bismaleimide of bis (aminophenoxy) benzene, and aniline and The reaction product of mixed polyamine, which is a reaction product of formalin, and maleic anhydride may be mentioned, but the present invention is not limited thereto. Further, these maleimide compounds may be used as a mixture of two or more kinds, and N-allyl maleimide, N-propyl maleimide,
A monomaleimide compound such as N-hexylmaleimide or N-phenylmaleimide may be contained.

The maleimide resin is preferably used in combination with a curing agent or a reactive diluent. 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 ester represented by the following general formula is also suitable as the thermosetting resin of the present invention.

[0022]

[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- such divalent hydrocarbon groups linked by a divalent atomic group) bismaleimide and the weight ratio of cyanate ester 0/10
It is used in the range of 0 to 70/30. The case of 0/100 is a cyanate resin, but this is also suitable for the present invention. It has a characteristic that the water absorption of the cured product is low.

Further, 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]) Component [B]
Is a block copolymer composed of an aromatic oligomer and a siloxane oligomer.

The aromatic oligomer moiety in the block copolymer composed of the aromatic oligomer and the siloxane oligomer used as the constituent element [B] is a divalent group such as 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. Further, it is preferable that the aromatic oligomer portion has an imide skeleton [(—CO—) ₂ N—] and an amide skeleton (—NHCO—) because both heat resistance and toughness are provided. 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 portion have an aromatic structure, but the aromatic unit may have a substituent such as chlorine, lower alkyl, phenyl and the like. .

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

Preferred examples of the 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 the diamino compound are diaminodiphenylmethane, metaphenylenediamine, paraphenylenediamine, diaminodiphenyl ether, diaminodiphenyl sulfone, 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.

The constituent element [B] has a siloxane oligomer as a block copolymerization component.

Siloxane is represented by the following formula.

[0031]

[Chemical 5] (However, in the formula, R ₂ is a divalent organic group, R ₃ is a monovalent organic group, and R ₂ and R ₃ may be the same or different, and n is an integer of 1 to 20.) Dimethyl siloxane is preferred, but phenyl siloxane and copolymers thereof 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 or a polyamide-siloxane block copolymer.

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 the constituent element [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 composed of two kinds of chain parts, but the ratio of the chain lengths of each is such that the aromatic oligomer chain part has a higher molecular weight than the siloxane chain part. It is preferable to increase The preferred number average molecular weight ratio is aromatic oligomer chain part / siloxane chain part = 1 to 20. 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 2 to 1
The range is 0.

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 preferably 10 to 20% by weight.

(Description of Component [C]) Component [C]
Is silicone fine particles. Silicone is a polymer having a repeating (—SiO—) _n siloxane bond as the main chain.

Since the constituent element [C] has a similar structure to the siloxane chain part of the constituent element [B], it has a high affinity with the constituent element [B], so that the toughness when used in combination with the constituent element [B]. A cured product having a phase separation structure suitable for improvement is provided.

The use of solid fine particles as the constituent [C] is excellent because the heat resistance and elastic modulus of the cured product are maintained. Further, the phase separation form of the cured product is less dependent on the curing conditions, and the physical properties are stable.

Both spherical and non-spherical fine particles can be used. When the spherical fine particles are used, the viscosity of the resin composition is lower than that when the resin composition is non-spherical, and therefore it is excellent in processability when used as a prepreg or an adhesive, which is preferable.

As the silicone fine particles, there are resin type and rubber type depending on the elasticity, and both are suitable for the present invention because they give a cured product having high toughness. The rubber type is more preferable when the toughness of the cured product is more important than the elastic modulus maintenance.

As commercial products of silicone rubber fine particles,
For example, Toray Dow Corning Silicone Co., Ltd., E-
601 and E-602. Examples of commercially available silicone resin fine particles include R-923, R-925 and R manufactured by Toray Dow Corning Silicone Co., Ltd.
-930 etc. are mentioned.

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 are an epoxy group and an amino group.

When the constituent element [C] is used in combination with the constituent element [B], it is possible to obtain resin toughness which is difficult to achieve by adding only the constituent element [B]. Conversely speaking, the addition amount of the constituent element [B] required to obtain the same level of toughness can be reduced. 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 toughness improving effect is small, and if it is more than this range, heat resistance and workability tend to deteriorate. It is more preferably 3 to 10% by weight, and further 4 to 8% by weight.

The addition amount of the constituent element [C] is the same as the constituent element [B].
From the viewpoint of improving the toughness and maintaining the elastic modulus, it is preferable that the amount is less than the addition amount.

(Description of Cured Product) By curing the above resin composition, a phase containing the following constituent [E] as a main component, a phase containing [F] as a main component, and a phase consisting of [G] A resin cured product is obtained in which each has a separated structure, and the phase composed of the constituent element [G] is contained in the phase whose main component is [F].

[E]: Epoxy resin, cyanate resin,
At least one thermosetting resin selected from bismaleimide resin [F]: Thermoplastic resin containing silicon [G]: Silicon fine particles When the above resin composition is cured, the constituent element [E] is contained as a main component. A phase and a phase mainly composed of the constituent element [F] are microphase-separated. At this time, the silicone fine particle phase composed of the constituent element [G] is localized in the phase mainly composed of the constituent element [F]. Is preferable. In particular, it is preferable that 70% or more of the total amount of the constituent element [G] is localized in the phase containing the constituent element [F] as the main component because the toughness improving effect becomes large. It is considered that this is because the plastic deformation ability originally possessed by the constituent element [F] is effectively extracted due to the presence of the constituent element [G]. The material of the constituent element [G] has a higher affinity for the constituent element [F] than for the constituent element [E], and thus forms such a phase-separated structure.

Further, as the phase separation form of the cured resin, it is preferable that at least the phase containing the constituent [F] as a main component has a three-dimensional continuous structure for improving the toughness. More preferably, the phase having the constituent element [F] as the main component and the phase having the constituent element [E] as the main component both have a continuous structure. 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 phase separation structure period formed from the phase containing [E] as a main component and the phase containing [F] as a main component is about 0.01 to 10 μm because the toughness improving effect is large. More preferably
It is about 0.1 to 3 microns.

The constituent element [G] is preferably localized in a phase containing the constituent element [F] as a main component, and the toughness is improved when the dispersed particle size is about 0.01 to 110 cron. Great effect and preferable. 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 [F] 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 constituent [G] into the phase containing the constituent [E] as the main component and the phase containing the constituent [F] as the main constituent is about 2000 times the above-mentioned micrograph. Copy, and cut out the part corresponding to the constituent element [G] existing in each phase, weigh it, or measure it with an image analyzer and compare the areas, and measure this at at least 5 points The average value is used.

The present invention includes components [A], [B], and [C].
A prepreg comprising a resin composition consisting of and a reinforcing fiber is provided. Also provided is a fiber-reinforced plastic having high toughness and high strength, which comprises a cured product made of the constituent elements [E], [F] and [G] and a reinforcing fiber.

The reinforcing fiber is a fiber generally used as an advanced composite material and having good heat resistance and tensile strength. 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, which uses the above resin as a matrix, has a characteristic that it has good tackiness and drapability because of its low resin viscosity. In addition, there is an advantage in the manufacturing process that it is easy to coat the resin and impregnate the reinforcing fiber strand during manufacturing of the prepreg.

The fiber reinforced plastic consisting of the constituent elements [E], [F], [G] and the 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.

[0059]

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

Example 1 Part A: Synthesis of Reactive Polyimide-Siloxane Oligomer 392 g (0.91) under nitrogen substitution in a 3000 ml separable flask equipped with a nitrogen inlet, thermometer, stirrer and dehydration trap. mol) bis [4- (3-aminophenoxy) phenyl] sulfone (BAPS-M), 39 g (0.11 mol) 9,
9'-bis (4-aminophenyl) fluorene (FDA),
147 g (0.11 mol) of NH ₂ equivalent 650 amino-terminated dimethylsiloxane BY-16-853 (manufactured by Toray Dow Corning Silicone Co., Ltd.) was added to 2000 ml of N-methyl-2-pyrrolidone (N
It was dissolved in MP) with stirring. 300 g (1.02 mol) of solid biphenyltetracarboxylic dianhydride was added little by little thereto, 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, it was diluted with double NMP and slowly poured into 20 l of acetone to precipitate the amine-terminated siloxane polyimide oligomer as a solid product. And the precipitate 20
It was vacuum dried at 0 ° C.

The number average molecular weight (Mn) of this oligomer was measured by gel permeation chromatography (GPC) using a dimethylformamide (DMF) solvent and found to be 5,500 in terms of polyethylene glycol (PEG).
The glass transition point is 22 according to the differential thermal analyzer (DSC).
It was 3 ° C. 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: Preparation of Resin and Measurement of Resin Physical Properties In a beaker, 25 parts of the above-mentioned polyimide siloxane block copolymer oligomer of Part A 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 at 140 ° C. for 10 minutes to dissolve.

A vacuum pump was connected to the container to perform degassing under vacuum, and then the mold was subjected to a mold release treatment in which the contents were preheated to 120 ° C. (dimensions of voids were 120 × 120 × 3 mm).
). 130 ° C for 2 hours in the oven + 180 ° C
The resin was cured for 2 hours to prepare a 3 mm thick resin cured plate.

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 1090 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 two phases together form a continuous phase was observed, and one phase was in the visual field. 78% 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 resin B was prepared in a kneader in advance and thinly applied on release paper to form 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 650 poise at 80 ° C.

A unidirectional carbon fiber A was sandwiched between resin films from above and below and impregnated with a resin to produce a prepreg. The prepreg had a carbon fiber basis 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 having the following composition: phenol novolac type epoxy resin (manufactured by Yuka Shell Epoxy Co., Epicoat 154) ) 40 parts by weight Bisphenol A type epoxy resin (Epicote 825, manufactured by Yuka Shell Epoxy Co., Ltd.) 30 parts by weight Bisphenol F type epoxy resin (Dainippon Ink and Machinery Co., Ltd.) Manufactured by Epicron 830) 30 parts by weight Polyimide siloxane block copolymer oligomer described in part A 25 parts by weight Silicone rubber fine particles (E-601, manufactured by Toray Dow Corning Silicone Co., Ltd.) ) 12 parts by weight 4,4'-diaminodiphenyl sulfone (Sumicure S, manufactured by Sumitomo Chemical Co., Ltd.) - 34 by weight part toughness G _IC of the prepreg to pull in one direction was measured interlayer toughness of the composite for a laminate of 20 layers peeled mode was 830J / m ² (double cantilever beam method).

(± 25 / ± 25/90) 10 with _S configuration
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 65.5 ksi.

Using a cured plate obtained by laminating 24 layers of prepregs 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 11.4 ksi.

A cured plate obtained by laminating 6 layers of prepregs in one direction and molding was used. 82 after water absorption in warm water (72 ° C.) for 2 weeks
The compressive strength at ℃ was determined according to SACMA SRS1-88, it was 191 ksi.

Example 2 Part A: Synthesis of Reactive Polyimide-Siloxane Oligomer 218 g (0.75) under nitrogen substitution in a 3000 ml separable flask equipped with a nitrogen inlet, thermometer, stirrer and dehydration trap. 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 (Toray Dow Corning Silicone Co., Ltd.)
Was prepared and dissolved in 2000 ml of N-methyl-2-pyrrolidone (NMP) with stirring. 305 g (0.85 mol) of solid diphenylsulfone tetracarboxylic acid dianhydride "Ricacid DSDA" (manufactured by Shin Nippon Rika Co., Ltd.) was added little by little, and the mixture was stirred at room temperature for 3 hours and then heated to 120 ° C. And stirred for 2 hours. Return the flask to room temperature, and add 50 ml of triethylamine and 50 ml of toluene.
After adding ml, heat up again and azeotropically dehydrate at 160 ° C
ml water was obtained. After cooling the reaction mixture, it was diluted with double volume of NMP 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: Preparation of Resin 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 "Epicoat 154" (manufactured by Yuka Shell Epoxy Co., Ltd.) , Bisphenol A type epoxy resin "Epicoat 825" (made by Yuka Shell Epoxy Co., Ltd.) 30
Part, bisphenol F type epoxy resin "Epiclon 83
30 parts of 0 "(manufactured by Dainippon Ink and Chemicals Co., Ltd.) were weighed. The oligomer was dissolved in the epoxy resin by heating it at 120 ° C. for 2 hours. Then, at 60 ° C., silicone resin fine particles R-930 ( Toray Dow Corning
12 parts of Silicone Co., Ltd. was added and mixed for 30 minutes with stirring. Furthermore, 34 parts of 4,4 'diaminodiphenyl sulfone "Sumikyu S" (Sumitomo Chemical Co., Ltd.) was added to give 14
The mixture was mixed and dissolved at 0 ° C for 10 minutes.

A vacuum pump was connected to the container to perform vacuum degassing, and then the mold was subjected to a mold release treatment in which the contents were preheated to 120 ° C. (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 202.degree. The above sample was cut out from this, and the fracture strain energy release rate G _IC was measured to be 970 J / m ² ,
The flexural modulus E was 350 kg / mm ² . Here, the flexural modulus was measured according to ASTM D790. Also, G _IC
Is the stress intensity factor K _IC obtained by ASTM E399-83, Poisson's ratio γ, and bending elastic modulus E from G _IC = K _IC
Calculated according to 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. 80% 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.

[Comparative Example 1] The same resin as in Example 1 was used as the matrix resin except that the silicone fine 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 the prepreg in which 20 layers were laminated in one direction was 410 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 46.8 ksi, which was inferior to the examples. [Comparative Example 2] The same procedure as in Example 1 was carried out using the same matrix resin as in Example 1 except that the amount of polyimide siloxane block copolymer oligomer added was increased to 50 parts by weight and the silicone rubber particles were removed. I repeated. The resin viscosity was higher than in Example 1 and was 9600 poise at 80 ° C.

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 a low tack, and has a drapability as in Example 1.
Was significantly inferior to.

The toughness G _{IC in the} peeling mode of a prepreg having 20 layers laminated in one direction was 570 J / m ² (double cantilever beam method), which was 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 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 polyimide siloxane block copolymer oligomer was omitted.

The fracture 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 prepreg 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.

[0089]

INDUSTRIAL APPLICABILITY The resin composition of the present invention can provide a prepreg excellent in tackiness and drape, and can be cured to provide 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 79/08 LRC

Claims (10)

[Claims] 1. A 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 and siloxane oligomer [C]: silicone fine particles 2. The resin composition according to claim 1, wherein the constituent element [A] is an epoxy resin containing an aromatic amine curing agent. 3. The resin composition according to claim 1, wherein the constituent element [A] is a maleimide resin containing a diallyl compound. 4. The resin composition according to claim 1, wherein the constituent element [B] is reactive with the constituent element [A]. 5. The molecular weight of component [B] is 2000-10.
It is the range of 000, The resin composition of Claim 1 characterized by the above-mentioned. 6. A prepreg comprising the resin composition according to claim 1 and a reinforcing fiber. 7. A phase containing the following constituent [E] as a main component,
The phase composed mainly of [F] and the phase composed of [G] are separated, and the phase composed of the constituent element [G] is [F].
A resin cured product, which is contained in a phase containing as a main component. [E]: At least one thermosetting resin selected from the group consisting of epoxy resin, cyanate resin and bismaleimide resin [F]: Thermoplastic resin containing silicon [G]: Silicon fine particles 8. The cured resin product according to claim 7, wherein 70% or more of the total amount of the constituent element [G] is present in the phase containing [F] as a main component. . 9. The cured resin product according to claim 7, wherein the phase containing the constituent [E] as a main component and the phase containing the constituent [F] as a main component each have a continuous structure. 10. A fiber-reinforced plastic comprising the resin cured product according to claim 7 and a reinforcing fiber.