JPH0689259B2 - Hybrid fiber reinforced plastic composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to specific inorganic fibers and carbon fibers, glass fibers, boron fibers, alumina fibers, silicon nitride fibers, aramid fibers, silicon carbide fibers and carbon as core wires. Of silicon carbide fiber and Si-M-C-O fiber (M represents Ti or Zr), which is a hybrid fiber with at least one fiber, and a plastic matrix. An excellent hybrid fiber reinforced plastic composite material.

(Prior Art and Problems Thereof) Conventionally, as a reinforcing material, in order to utilize the characteristics of various materials, research on a hybrid fiber-reinforced plastic composite material in which two or more kinds of fibers are put in a matrix has been advanced.

For example, as hybrid fibers for reinforcing plastics such as epoxy resin, modified epoxy resin, polyester resin, and polyimide resin, carbon / glass, carbon / aramid fiber (Kevlar), boron / carbon, boron / Kevlar, boron / glass, Research has been conducted on ceramic fibers / Kevlar and Kevlar / Glass, but carbon / glass and carbon / Kevlar are overwhelmingly large, and practical applications are almost limited to these two types.

However, when carbon fiber is used, the wettability with the resin is inferior, so the surface treatment of the fiber is necessary, and even if the carbon fiber subjected to the surface treatment is used, the composite material has low interlaminar shear strength and is perpendicular to the fiber. Since the tensile strength in the direction is low, the resin and fiber are easily peeled off, the fatigue strength is low, and the bending impact value is low, which easily causes breakage, which is a practical problem.
When glass fiber is used, a sufficient reinforcing effect cannot be obtained due to low tensile strength and elastic modulus. When silicon carbide fibers with boron fibers and carbon fibers as core wires are used, plastic composite materials with these fibers as reinforcements do not have high fiber volume ratios and are mechanical The characteristics are not sufficient.

When aramid fiber is used, its fatigue strength is low because it is weak against compression.

In order to solve these problems, Japanese Unexamined Patent Publication No. 62-7737 discloses Si-M-C-O fibers (M represents Ti or Zr), carbon fibers, glass fibers, boron fibers, and aramid fibers. And a hybrid fiber-reinforced plastic composite material in which a hybrid fiber with at least one fiber selected from the group consisting of silicon carbide fibers having carbon as a core wire is used as a reinforcing material.

The present invention, compared with the hybrid fiber reinforced plastic composite material disclosed in the above publication, the elastic modulus is further improved,
Provide hybrid fiber reinforced plastic composite material that is very cost effective.

(Means for Solving Problems) The present invention provides a hybrid fiber-reinforced plastic composite material having improved mechanical properties and improving the above problems of each material of the hybrid fiber.

The inorganic fibers in the present invention have a high affinity with plastics and are highly flexible, so that they can be easily spun and woven, and supplement the above-mentioned drawbacks peculiar to other fibers to enhance the reinforcing effect. Therefore, the interlaminar shear strength and bending impact value are significantly improved in the reinforced plastic composite material using the hybrid fiber using the inorganic fiber specified in the present invention.

The composite material of the present invention is an inorganic fiber and a carbon fiber, a glass fiber, a boron fiber, an alumina fiber, a silicon nitride fiber, an aramid fiber, a silicon carbide fiber, a silicon carbide fiber having a carbon core wire, and a Si-M-C-O fiber. (M represents Ti or Zr.)
At least one element selected from the group consisting of titanium, zirconium and hafnium, in a plastic composite material in which a hybrid fiber with at least one fiber selected from the group consisting of: And an inorganic fiber obtained from a metal polycyclic aromatic polymer containing silicon,
The constituent component is selected from the group consisting of a) a radial structure, an onion structure, a random structure, a core radial structure, a skin onion structure and a mosaic structure derived from a polycyclic aromatic compound in a mesophase state which constitutes the polymer. At least one type of carbonaceous material having a crystalline alignment state, b) non-oriented crystalline carbon derived from an optically isotropic polycyclic aromatic compound containing an organic solvent insoluble component constituting the polymer, and / or Amorphous carbon, and c) an amorphous material consisting essentially of Si, M, C and O,
And / or substantially β-SiC, MC, a solid solution of β-SiC and MC and MC
_It is an aggregate of crystalline ultrafine particles of _{1-x with} a particle size of 500Å or less and amorphous SiO _y and MO _z. The proportion of constituent elements is Si; 5 to 70% by weight, M; 0.5 to 45% by weight. %,
C: 20-40% by weight and O: 0.01-30% by weight, Si-M-
C—O substance (wherein M is at least one element selected from Ti, Zr and Hf, and 0 <x <1, 0 <y ≦
2, 0 <z ≦ 2. ) Is a hybrid fiber reinforced plastic composite material.

The inorganic fiber in the present invention will be described first. In the following description, all "parts" are "parts by weight" and "%" is "% by weight".

The inorganic fiber in the present invention has the above-mentioned constituent component a),
It consists of b) and c), Si: 0.01-30%, M: 0.01
~ 10%, C; 65-99.9% and O; 0.001-10%, preferably S
i; 0.1 to 25%, M; 0.01 to 8%, C; 74 to 99.8% and O; 0.01
Substantially composed of ~ 8%.

The crystalline carbon, which is a constituent component of this inorganic fiber, has a crystallite size of 500 Å or less, and corresponds to a 3.2 Å (002) plane oriented in the fiber axis direction in a high resolution electron microscope having a resolution of 1.5 Å. It is an ultrafine graphite crystal that allows the observation of a fine lattice image. The crystalline carbon in the inorganic fiber may have a radial structure, an onion structure, a random structure, a core radial structure, a skin onion structure, a mosaic structure, a random structure including a partial radial structure, or the like. This is due to the presence of the mesophase polycyclic aromatic compound in the raw material.

The sum of constituents a) and b) of this inorganic fiber is 100
The ratio of component c) to parts is 0.015 to 200 parts,
Moreover, the ratio of the constituents a) and b) is 1: 0.02-4.

When the ratio of the constituent component c) to the total of 100 parts of the constituent components a) and b) is less than 0.015, it is almost the same as that of the pitch fiber, and improvement in oxidation resistance and wettability cannot be expected. If it exceeds, fine crystals of graphite are not effectively formed, and a fiber having a high elastic modulus cannot be obtained.

The inorganic fiber in the present invention is mainly composed of 1) a bond unit (Si—CH ₂ ), or a bond unit (Si—CH ₂ ) and a bond unit (Si—Si), and a hydrogen atom or a lower alkyl group in a side chain of a silicon atom. Group, having a side chain group selected from the group consisting of a phenyl group and a silyl group, the silicon atom of the main skeleton consisting of the above-mentioned binding unit, at least one atom selected from the group consisting of titanium, zirconium and hafnium, At least a part of the silicon atoms of the transition metal-containing organic silicon polymer bonded to at least a part of the silicon atoms directly or via an oxygen atom is a petroleum-based or coal-based pitch or an aromatic ring of its heat-treated product. 2) Random copolymer bound to carbon and 2) Polycyclic aromatization consisting of mesophase state or both mesophase and optically isotropic phase obtained by heat treatment of petroleum-based or coal-based pitch (Hereinafter, both are collectively referred to as "mesophase polycyclic aromatic compound") by heating and / or melting at a temperature in the range of 200 to 500 ° C to obtain a metal-containing polycyclic aromatic polymer. A first step, a second step of preparing and spinning a spinning solution for the metal-containing polycyclic aromatic polymer, and a third step of infusibilizing the spinning raw thread under tension or without tension
And a fourth step of firing the infusibilized spun fiber at a temperature in the range of 800 to 3000 ° C. in a vacuum or an inert gas atmosphere.

Each of the above steps will be specifically described.

First step: The organosilicon polymer, which is one of the starting materials, can be synthesized by a known method. For example, polymethylsilane obtained by the reaction of dimethyldichlorosilane and sodium metal is added in an inert gas at 400 It is obtained by heating to ℃ or more.

The organosilicon polymer, binding unit (Si-CH _2), or binding units (Si-Si) and mainly consists binding units (Si-CH _2), the total number pairing unit of coupling units (Si-CH ₂₎ (Si-S
The ratio of the total number of i) is in the range of 1: 0 to 20.

The weight average molecular weight (M _w ) of the organosilicon polymer is generally
Those having a molecular weight of 300 to 1000 and a _Mw of 400 to 800 are particularly preferable for preparing the random copolymer (2) which is an intermediate raw material for obtaining an excellent carbon-based inorganic fiber.

Another starting material, a polycyclic aromatic compound, is a pitch obtained from petroleum and / or coal, and a particularly preferable pitch is a heavy oil obtained by fluid catalytic cracking of petroleum,
It is a distillate component obtained by distilling the heavy oil or residual oil and pitch obtained by heat-treating them.

The pitch contains 5 to 98% of insoluble components in organic solvents such as benzene, toluene, xylene, and tetrahydrofuran.
%, Particularly 10 to 80% is preferable. When a pitch containing less than 5% by weight of the above insoluble component is used as a raw material, an inorganic fiber excellent in both strength and elastic modulus cannot be obtained,
Further, when a pitch of more than 98% by weight is used as a raw material, the molecular weight of the copolymer is drastically increased, and some coking may occur, making spinning difficult.

The weight average molecular weight (M _w ) of this pitch is 100 to 3000. The weight average molecular weight is a value determined as follows. That is, if the pitch does not contain the organic solvent insoluble matter for gel permeation chromatograph (GPC) measurement such as benzene, toluene, xylene, tetrahydrofuran, chloroform and dichlorobenzene, the GPC measurement is performed as it is, and the pitch is the above organic solvent insoluble matter. If it contains
Hydrogenation treatment is carried out under mild conditions, the organic solvent-insoluble matter is changed to the organic solvent-soluble component, and post-GPC measurement is carried out. The weight average molecular weight of the polymer containing the organic solvent insoluble matter is a value obtained by performing the same treatment as above.

The ratio of the pitch used is 83 to 4 per 100 parts of the organosilicon polymer.
It is preferably 900 parts. If the proportion of the pitch used is too small, the amount of silicon carbide component in the resulting inorganic fiber will be large, and it will not be possible to obtain an inorganic fiber having a high elastic modulus. If the proportion is too large, the silicon carbide component will be large. Is less, and it becomes impossible to obtain an inorganic fiber having excellent wettability to the matrix and oxidation resistance.

When the reaction temperature of the above reaction is excessively low, the bond between the silicon atom and the aromatic carbon is hard to be generated, and when the reaction temperature is excessively high, decomposition and high molecular weight of the generated precursor polymer (1) occur violently. Not preferable.

The precursor polymer (1) referred to here includes, in addition to the copolymer in which the organosilicon polymer and the pitch are bonded via the silicon-carbon linking group, the polycondensate of each of the organosilicon polymer and the pitch. .

Nitrogen, argon and the like are preferably used as the inert gas.

Next, the precursor polymer (1) and the transition metal compound represented by the formula MX ₄ are reacted in the temperature range of 100 to 500 ° C. The MX
_{In 4} , M is at least one element selected from Ti, Zr and Hf, and X is a compound capable of being bonded to silicon of the precursor polymer (1) directly or through an oxygen atom by condensation. However, a halogen atom, an alkoxy group or a complex-forming group such as β-diketone is preferable.

If the reaction temperature is excessively low, the condensation reaction between the precursor polymer (1) and the formula MX ₄ will not proceed, and if the reaction temperature is excessively high, the crosslinking reaction of the precursor polymer (1) via M will be excessive. And gelation occurs, the precursor polymer (1) itself condenses to a high molecular weight, or in some cases MX ₄ is volatilized to produce an excellent inorganic fiber. Polymer (2) cannot be obtained.

As an example, when M is Ti and X is OC ₄ H ₉ , the reaction temperature is suitably 200 to 400 ° C.

By this reaction, a random copolymer (2) in which at least a part of silicon atoms of the precursor polymer (1) is bonded to M directly or via an oxygen atom is prepared. The metal M can be bonded to the silicon atom of the precursor polymer (1) in a side chain form by a bonding mode such as -MX ₃ or -O-MX ₃ , or the silicon atom of the precursor polymer (1) can be directly bonded. Alternatively, a bonding mode of crosslinking via oxygen may be adopted.

As the method for preparing the random copolymer (2), in addition to the method described above, a method of reacting an organosilicon polymer with MX ₄ and further reacting the obtained product with pitch can be used. .

In the first step, finally, the random copolymer (2) and the mesophase polycyclic aromatic compound are heated and / or melted by heating to prepare a metal-containing polycyclic aromatic polymer.

Mesophase polycyclic aromatic compound, for example, heating petroleum-based or coal-based pitch in an inert gas to 300 ~ 500 ℃,
It can be prepared by polycondensation while removing the produced soft fraction.

If the polycondensation reaction temperature is too low, the condensed ring will not grow sufficiently, and if the temperature is too high, an insoluble and infusible product will be produced by coking.

The above mesophase polycyclic aromatic compound has a melting point of 200
~ 400 ℃, the weight average molecular weight of 200 ~ 10
It is 000.

Among mesophase polycyclic aromatic compounds, 20-100%
Those having an optical anisotropy of 3 to 100% and containing an insoluble matter in benzene, toluene, xylene or tetrahydrofuran are particularly preferable for obtaining an inorganic fiber having excellent mechanical performance.

The use ratio of the mesophase polycyclic aromatic compound is preferably 5 to 50,000 parts, more preferably 5 to 10,000 parts, per 100 parts of the random copolymer (2). If it is less than 5 parts, the mesophase content in the product is insufficient. Therefore, it is not possible to obtain a highly elastic fired yarn, and when it is more than 50,000 parts,
Insufficient silicon component makes it impossible to obtain an inorganic fiber having excellent wettability and oxidation resistance with respect to the matrix.

The random copolymer (2) and the mesophase polycyclic aromatic compound are heated and reacted and / or melted at 200 to 500 ° C. so that at least a part of the random copolymer (2) is a mesophase polycyclic aromatic compound. A metal-containing polycyclic aromatic polymer bound with is obtained. However, the bond here means a chemical bond between silicon of the random copolymer (2) and carbon of the polycyclic aromatic compound and the random copolymer (2).
It means a physical bond such as van der Waals bond between the polycyclic aromatic ring portion chemically bonded to silicon and the mesophase polycyclic aromatic compound.

When the melt-mixing temperature is lower than 200 ° C, an infusible portion is generated,
The system becomes inhomogeneous, which adversely affects the strength and elastic modulus of the inorganic fiber, and when the melt mixing temperature is higher than 500 ° C, the condensation reaction proceeds violently, the resulting polymer has a high melting point, and the spinning of the polymer is remarkable. It will be difficult.

The method for preparing the metal-containing polycyclic aromatic polymer,
In addition to the method described above, a method of reacting an organosilicon polymer with pitch, adding mesophase pitch and MX ₄ simultaneously or sequentially to the obtained product, and further reacting, is also possible.

The weight average molecular weight of the metal-containing polycyclic aromatic polymer is 20
It has a melting point of 200 to 400 ° C. at 0 to 11000.

Second step: The spinning polymer, which is the metal-containing polycyclic aromatic polymer obtained in the first step, is heated and melted, and in some cases, this is filtered to remove substances such as microgels and impurities that are harmful during spinning. This is spun by a commonly used synthetic fiber spinning device. The temperature of the spinning dope during spinning varies depending on the softening temperature of the raw polymer, but a temperature in the range of 220 to 420 ° C is advantageous.

In the spinning device, a spinning tube is attached if necessary,
After making the atmosphere in the spinning cylinder one or more atmospheres selected from the group consisting of air, inert gas, hot air, heat inert gas, steam, and ammonia gas, a small diameter is obtained by increasing the winding speed. Fibers can be obtained. The spinning speed in the melt spinning varies depending on the average molecular weight of the raw material, the molecular weight distribution, and the molecular structure, but is 50 to 5000.
It is preferably in the range of m / min.

Third step: The spun fiber obtained in the second step is infusibilized under the action of tension or no tension.

A typical infusibilizing method is a method of heating spun fibers in an oxidizing atmosphere. The temperature of infusibilization is preferably 50 to 400
The temperature is in the range of ° C. When the infusibilization temperature is excessively low, the polymer constituting the spinning yarn does not hang up, and
If this temperature is too high, the polymer will burn.

The purpose of infusibilization is to make the polymer that constitutes the spun fiber into an infusible or insoluble state of a three-dimensional structure so that it will not melt during the firing of the next step and will not fuse with adjacent fibers. Is. Examples of the gas forming the oxidizing atmosphere at the time of infusibilization include air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, and mixed gas thereof.

As another infusibilizing method different from the above, the spun fiber is infusibilized by γ-ray irradiation or electron beam irradiation while heating at low temperature in an oxidizing atmosphere or a non-oxidizing atmosphere under tension or no tension as necessary. Methods can also be employed.

The purpose of irradiating this γ ray or electron beam, by further polymerizing the polymer forming the spun fiber,
This is to prevent the spinning raw yarn from melting and losing the fiber shape.

The appropriate irradiation dose of gamma rays or electron beams is 10 ⁶ to 10 ¹⁰ rads.

Irradiation can be performed in a vacuum, an inert gas atmosphere, or an oxidizing gas atmosphere such as air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, or a mixed gas thereof.

The infusibilization by irradiation can be performed at room temperature, and if necessary, the infusibilization can be achieved by heating while heating in the temperature range of 50 to 200 ° C.

If the infusibilization is carried out under no tension, the spun fiber will have a wavy shape due to shrinkage, but in some cases it can be corrected in the firing step of the next step, tension is not always necessary, but tension acts In such a case, a good result can be obtained by applying a tension higher than the tension that can at least prevent the spun fiber from contracting and becoming wavy during infusibilization.

When infusibilizing, the tension applied is 1 to 500 g / mm ²
The range is preferable, and even if a tension of 1 g / mm ² or less is applied, it is not possible to give tension that does not cause the fiber to sag, and
The fiber may break when a tension of 0 g / mm ² or more is applied.

Fourth step: The infusible yarn obtained in the third step and the inorganic fiber mainly composed of carbon, M, silicon and oxygen are obtained by firing at a temperature in the range of 800 to 3000 ° C. in a vacuum or an inert gas atmosphere. can get.

In the firing step, it is not always necessary to apply tension, but high-temperature inorganic fiber with less bending can be obtained by firing at high temperature while applying tension in the range of 0.001 to 100 Kg / mm ² .

In the heating process, mineralization becomes severe from about 700 ℃,
It is estimated that mineralization is almost completed at about 800 ° C. Therefore, the firing is preferably performed at a temperature of 800 ° C. or higher. Moreover, since an expensive apparatus is required to obtain a temperature higher than 3000 ° C., firing at a temperature higher than 3000 ° C. is impractical in terms of cost.

The form of the Si-M-C-O substance that is the constituent component c) is determined by the manufacturing conditions adopted in the first to fourth steps. Generally speaking, if the firing temperature in the fourth step is lower than, for example, 1000 ° C., the constituent component c) is Si, M,
It is substantially composed of an amorphous material composed of C and O.

On the other hand, when the firing temperature in the fourth step is, for example, 1700 ° C. or higher, the constituent component c) is substantially β-SiC, MC, β-SiC and MC.
Solid solution and MC _1-x (provided that 0 <x <1) and ultra-fine particles with a particle size of 500Å or less and SiO _y (provided that 0 <y ≦
2), MO _z (where 0 <z ≦ 2), and is substantially composed of an amorphous aggregate.

At intermediate temperatures, component c) is composed of a mixed system of aggregates. Further, the amount of oxygen in the inorganic fiber can be controlled by, for example, the addition ratio of MX ₄ in the first step or the infusibilizing condition in the third step.

Further, the distribution state of the constituent component c) can be controlled by the atmosphere during firing and the size and concentration of the mesophase in the raw material. For example, when the mesophase is grown large, the constituent component c) tends to be extruded into the fiber surface phase.

Fibers constituting the hybrid fiber together with the inorganic fiber in the present invention, carbon fiber, glass fiber, boron fiber,
Alumina fiber, silicon nitride fiber, aramid fiber, silicon carbide fiber, silicon carbide fiber having carbon core wire and Si-M-
It is selected from C—O fibers (M represents Ti or Zr).

The above Si-M-C-O fibers are (i) amorphous consisting essentially of Si, M, C and O, or (ii) substantially β-SiC, MC, β-SiC and MC. Solid solution of
Each of the crystalline ultrafine particles having a particle diameter of 500 Å or less of MC _{1-x and} an aggregate composed of amorphous SiO ₂ and MO ₂ , or (iii) the amorphous material of (i) above and the amorphous material of (ii) above An inorganic fiber composed of a mixed system of crystalline ultrafine particle aggregates (where M represents Ti or Zr and 0 <x <1). This inorganic fiber can be prepared, for example, by the method described in JP-B-60-1405, JP-A-58-5286, JP-A-60-20485 and JP-A-59-44403.

The fiber used as a reinforcing material in the present invention is a method in which the fiber itself is blended in a uniaxial direction or a multiaxial direction, or various woven fabrics such as plain weave, satin weave, dummy weave, twill weave, leno weave, spiral weave, and three-dimensional woven fabric. There is a method of using it or a method of using it as chopped fiber.

The proportion of the inorganic fibers defined in the present invention in the hybrid fibers is 10% or more, preferably 20% or more. When it is lower than 10%, the bond strength between the plastic and the inorganic fiber is improved,
The effect of improving the mechanical properties, which is the object of the present invention, that is, the improvement of the strengthening efficiency and the reduction rate of the fatigue strength are poor, that is, the improving effects of the interlaminar shear strength, the bending impact value and the fatigue strength are decreased.

Looking at the hybrid state of hybrid fibers by form, (1) an inter-layer hybrid in which a layer of a certain type of fiber and a layer of another type of fiber are laminated (2) an intra-layer hybrid that has already been hybridized in one layer Two types are basic,
(3) There are combinations of them. The main types of combinations are the following 6 types.

(A) Lamination of single-layer tape (one in which heterogeneous fibers are alternately laminated in layers) (b) Sandwich type (one in which heterogeneous fibers are laminated in a sandwich) (c) Rib reinforcement (d) Mixed woven tow (Hybrid of heterogeneous fibers in unit of single fiber) (e) Lamination of mixed woven tape (hybrid of heterogeneous fibers in layers in yarn units) (f) Epoxy as a plastic in the present invention Resin,
Polyester resin, phenol resin, polyimide resin,
Polyurethane resin, polyamide resin, polycarbonate resin, silicone resin, fluorine resin, nylon resin, polyphenylene sulfide, polybutylene terephthalate, polyethylene, polypropylene, modified polyphenylene oxide, polystyrene, ABS resin, vinyl chloride resin, polyether etherketone resin, It is a bismaleimide resin or the like, and a mixture thereof may be used.

The hybrid fiber-reinforced plastic composite material can be produced by a method known per se, and includes, for example, (1) hydration method, (2) matched metal die method, (3)
The breakaway method, (4) filament winding method, (5) hot pressing method, (6) autoclave method, (7) continuous drawing method, etc. can be adopted.

(1) According to the hand lay-up method, first, the hybrid fiber is cut and spread on a mold, and the catalyst-added plastic is brushed on with a brush or a roller, and then naturally cured to release the mold. Can be a composite material.

(2) According to the matched metal die method, a composite material can be obtained by heating and pressurizing a hybrid fiber, which is impregnated with plastic, a curing agent, a filler, and a thickening agent in advance. SMC method (She
et Molding Compound), BMC method (Bulk Molding Compoun
Either of d) can be selected and used.

(3) According to the breakaway method, a sheet of hybrid fiber is preliminarily impregnated with plastic to form a pre-cured prepreg, which is wound around a tapered mandrel, and after curing, extracted as a composite material. can do.

(4) According to the filament winding method, a hybrid fiber impregnated with a thermosetting resin such as an epoxy resin or an unsaturated polyester resin is wound around a mandrel,
After the resin is cured, it can be demolded into a composite material. This method includes a wet method and a dry method (method using a prepreg tape).

(5) According to the hot pressing method, the prepreg sheets can be laminated in one direction or at an arbitrary angle and then pressed and heated by the hot press to form a plate-shaped composite material.

(6) According to the autoclave method, a prepreg is laminated on a molding die, wrapped with a special rubber, put in a vacuum state, placed in a pressurizing pot, and heated and pressed to cure to obtain a composite material. Suitable for complex molding.

(7) According to the continuous drawing method, the hybrid fiber and the plastic are separately separated, supplied to the molding machine, mixed in front of the molding die, and passed through a heating furnace on the way to continuously elongate them. It can be a lengthy composite material.

The tensile strength (σ _c ) of the composite material produced from the hybrid fiber and the plastic matrix is represented by the following formula.

_{σ c = σ f V f +} σ M V M σ c: tensile strength of the composite sigma _f: tensile strength of the hybrid fiber sigma _M: the plastic matrix tensile strength V _f: volume percentage V _M of the hybrid fibers: the volume of the plastic matrix Percentage As shown in the above equation, the strength of the composite material increases as the volume ratio of the hybrid fibers in the composite material increases. Therefore, in order to manufacture a composite material having high strength, it is necessary to increase the volume ratio of the hybrid fiber to be composited. However, when the volume ratio of the hybrid fibers exceeds 80%, the amount of the plastic matrix is small, and it is not possible to sufficiently fill the gaps of the hybrid fibers with the plastic matrix. The strength as shown is not exerted. Further, as the volume ratio of the fibers is lowered, the strength of the composite material is lowered as shown by the above formula, so in order to obtain a practical composite material, 10
% Or more hybrid fibers must be combined. Therefore, in the production of the hybrid fiber-reinforced plastic composite material of the present invention, the best effect is obtained when the volume ratio of the hybrid fiber to be composited is 10 to 80%, more preferably 25 to 70%.

Various mechanical properties in the specification were determined according to the following measuring methods.

(A) Interlaminar shear strength 10 × 12 on 2 pins (length 20mm) with radius of curvature 6mmφ
Place a composite material of × 2 mm, compress with an indenter with a tip radius of curvature of 3.5 mmR, perform a test by a so-called three-point bending method, and measure the interlaminar shear stress. It is indicated by shear stress (kg / mm ² ).

(B) Bending impact value The bending impact value was measured by the Charpy test method (JIS K7111) by 3-point bending. Displayed by bending impact value (kgcm / cm ² ).

(C) Tensile strength and tensile modulus The thickness of the test piece is 2 mm, and the thickness of the test piece is about 1 mm with a curvature of 125 mmR in the plate thickness direction at the center. Measurement of tensile strength is 1 mm / m
I went in. It is indicated by tensile strength (kg / mm ² ) and elastic modulus (t / mm ² ).

(D) Flexural strength and flexural modulus The thickness of the test piece is 2 mm, and a curvature of 125 mmR is applied in the plate thickness direction at the center to finish the thickness to about 1 mm. The test is performed by the three-point bending method, and the bending strength (kg / mm ² ) and bending elastic modulus (t / mm ² ) are displayed.

Among the various mechanical properties described above, the interlaminar shear strength and the bending impact value are indexes indicating the bond strength between the plastic and the fiber. When the interlaminar shear strength is weak, the bonding strength between the resin and the fiber is weak, and the fiber is easily separated from the resin after long-term use. In addition, when the bending impact value is low, a practical problem of breakage due to momentary impact occurs.

(Effect of the invention) The hybrid fiber-reinforced plastic composite material of the present invention is excellent in mechanical properties such as interlaminar shear strength and bending impact value, and is excellent in bond strength between the plastic and the fiber. It withstands use in various environments. Therefore, it can be used in various fields which could not be used satisfactorily with conventional hybrid fiber-reinforced plastic composite materials. Such applications include building materials, aircraft, materials for space development equipment, materials for ships, materials for land transportation equipment, materials for corrosion-resistant equipment, electrical materials, sports equipment, equipment elements, medical equipment materials, acoustic equipment materials. Applications in various fields such as can be exemplified.

(Examples) The present invention will be described below with reference to Examples.

Reference Example 1 (Production of Organosilicon Polymer) 2.5 l of anhydrous xylene and 40 parts of sodium were placed in a 5 l three-necked flask.
0 g was added, the mixture was heated to the boiling point of xylene under a nitrogen gas stream, and dimethyldichlorosilane 1 was added dropwise over 1 hour.
After completion of the dropping, the mixture was heated under reflux for 10 hours to form a precipitate. The precipitate was filtered, washed with methanol and then with water to obtain 420 g of white powdery polydimethylsilane.

This polydimethylsilane 400g, a gas introduction pipe, a stirrer,
Charge a 3 liter three-necked flask equipped with a condenser and a distillation tube,
Heat treatment was carried out at 420 ° C. under a nitrogen stream of 50 ml / min while stirring to obtain 350 g of a colorless transparent slightly viscous liquid in the distilling receiver.

The number average molecular weight of this liquid was 470 as measured by the vapor pressure osmosis method.

The infrared absorption spectrum of this substance was measured and found to be 65
Absorption of Si-CH ₃ at 0-900 cm ^-1 and 1250 cm ^-1 , Si at 2100 cm ^-1
Absorption of -H, Si-CH ₂ -Si absorption of the of 1020 cm ^-1 and near 1355 cm ^-1, absorption of CH was observed at 2900 cm ^-1 and 2950 cm ^-1,
Further, when the far-infrared absorption spectrum of this substance was measured, absorption of Si-Si was observed at 380 cm ^-1 , and thus the obtained liquid substance was mainly composed of (Si-CH ₂ ) bond units and (Si-Si). It was found to be an organosilicon polymer having a bonding unit and having a hydrogen atom and a methyl group in the side chain of silicon.

From the measurement results of the magnetic resonance analysis and the infrared absorption analysis, the organosilicon polymer showed that the total number of (Si—CH ₂ ) bond units versus (Si
It was confirmed that the polymer had a ratio of the total number of -Si) bond units of approximately 1: 3.

300 g of the above organosilicon polymer was treated with ethanol to remove low molecular weight substances, and 40 g of a polymer having a number average molecular weight of 1200 was obtained.

Measurement of the infrared absorption spectrum of this material, the absorption peak similar to that described above was observed, the material consists predominantly (Si-CH ₂₎ coupling units and (Si-Si) bond unit, hydrogen on the side chain of the silicon It was found to be an organosilicon polymer having atoms and methyl groups.

From the measurement results of the magnetic resonance analysis and the infrared absorption analysis, the organosilicon polymer showed that the total number of (Si—CH ₂ ) bond units versus (Si
It was confirmed that the polymer had a ratio of the total number of -Si) bond units of about 7: 1.

Reference Example 2 (Production of Inorganic Fiber I) Of the petroleum fraction, a high boiling point substance such as light oil or higher is subjected to fluid catalytic cracking at a temperature of 500 ° C. in the presence of a silica / alumina type cracking catalyst.
Fractionation was performed to obtain a residue from the bottom of the column. Hereinafter, this residue is referred to as FCC slurry oil.

As a result of elemental analysis, the FCC slurry oil had an atomic ratio of oxygen atoms to hydrogen atoms (C / H) of 0.75, and an aromatic carbon ratio by magnetic resonance analysis of 0.55.

500 g of the above FCC slurry oil was heated for 1 hour at 450 ° C under a nitrogen gas flow of 1 / min, the distillate at the same temperature was distilled off, and the residue was hot filtered at 200 ° C to make it infusible at the same temperature. The portion was removed to obtain 225 g of a light material removal pitch.

The light content removal pitch was an optically isotropic pitch containing 75% xylene insoluble matter.

In parallel with this, 400 g of the above FCC slurry oil was heated to 450 ° C. under a nitrogen gas stream, the distillate at the same temperature was distilled off, and the residue was filtered while hot at 200 ° C. The fused portion was removed to obtain 180 g of a light material removal pitch. 180 g of the obtained light component removal pitch was subjected to polycondensation at 400 ° C. for 7 hours under a nitrogen stream while removing the light component produced by the reaction, to obtain a heat treated pitch of 85 g.

This heat treatment pitch has a melting point of 268 ° C, xylene insoluble content of 92%,
It was a mesophase polycyclic aromatic compound containing 12% quinoline-insoluble matter and having an optical anisotropy of 89% by observation of the polished surface with a polarizing microscope.

21 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene were added to 49 g of the light content removal pitch, the temperature was raised with stirring, and xylene was distilled off, followed by reaction at 400 ° C. for 6 hours to give 39 g of the precursor polymer ( 1) was obtained.

As a result of infrared absorption spectrum measurement, this precursor polymer (1) was found to have Si-H bonds (IR: 2100c) present in the organosilicon polymer.
m ^-1 ) decrease and new Si-C (carbon of benzene ring)
The formation of a bond (IR: 1135 cm ^-1 ) was confirmed to indicate that the organosilicon polymer is a copolymer having a part of silicon atoms directly bonded to a polycyclic aromatic ring.

To 39 g of the precursor polymer (1), tetraoctoxytitanium [Ti (OC
₈ H ₁₇ ) ₄ ] 2.75 g xylene solution (25% xylene solution 11 g)
After xylene was distilled off, the mixture was reacted at 340 ° C. for 2 hours to obtain 38 g of a random copolymer (2).

This copolymer did not contain a xylene-insoluble portion, had a weight average molecular weight of 1650 and a melting point of 272 ° C.

35 g of the random copolymer (2) and 90 g of the mesophase polycyclic aromatic compound were mixed and melt-heated at 310 ° C. for 1 hour under a nitrogen atmosphere to obtain a metal-containing polycyclic aromatic polymer in a uniform state. .

This polymer had a melting point of 272 ° C. and contained 59% xylene-insoluble matter.

Using the above high molecular weight material as a raw material for spinning, using a metal nozzle having a nozzle diameter of 0.15 mm, melt spinning is performed at 340 ° C., the obtained spinning raw yarn is infusible at 300 ° C. in air, and further in an argon atmosphere. Firing was performed at 1300 ° C. to obtain an inorganic fiber having a diameter of 10 μm.

This fiber has a tensile strength of 320 Kg / mm ² and a tensile elastic modulus of 32 t / mm ² , and the fracture surface was observed using a scanning electron microscope.As a result, a coral-like tandam and radial mixed structure with multiple layers of crystal layers were observed. Met.

Reference Example 3 (Production of Inorganic Fiber II) 39 g of the precursor polymer (1) obtained in Reference Example 2 was added with an ethanol-xylene solution (1.5%) of 5.4 g of tetrakisacetylacetonatozirconium, and xylene and ethanol were distilled off. Then, the mixture was polymerized at 250 ° C. for 1 hour to obtain 39.5 g of a random copolymer (2).

20 g of this polymer and 50 g of the mesophase polycyclic aromatic compound obtained in Reference Example 2 were finely pulverized and mixed, melted at 350 ° C. in a spinning cylinder, and spun at 340 ° C. using a nozzle having a nozzle diameter of 0.2 mm, The obtained spun yarn is infusibilized in air at 250 ° C, and further fired at 1400 ° C in an argon atmosphere, and an inorganic fiber with a diameter of 11μ II
Got

This fiber had a tensile strength of 325 kg / mm ² and a tensile elastic modulus of 35 t / mm ² .

Reference Example 4 (Structure of Inorganic Fiber III) The procedure of Reference Example 2 was repeated except that the amounts of the light content removal pitch and the organosilicon polymer were changed to 60 g and 40 g, respectively.
g of precursor polymer (1) was obtained.

Hafnium chloride 7.2 is added to 40 g of this precursor copolymer (1).
g of ethanol-xylene solution (1.5%) was added, and xylene and ethanol were distilled off, followed by polymerization at 250 ° C. for 1 hour to obtain 43.5 g of a random copolymer (2).

After 20 g of this polymer and 80 g of the mesophase polycyclic aromatic compound obtained in Reference Example 2 were finely pulverized and mixed, 3
Melt degassing at 50 ° C, melt spinning at 350 ° C, infusibilizing at 270 ° C and firing at 1200 ° C in argon 1
2.5 μm of inorganic fiber III was obtained.

The tensile strength of this fiber was 315 kg / mm ² , and the tensile elastic modulus was 35 t / mm ² .

Reference Example 5 (Production of Inorganic Fiber IV) 700 g of the FCC slurry oil obtained in Reference Example 2 was heated at 450 ° C. for 0.5 hours under a nitrogen gas stream of 2 l / min to distill off the distillate at the same temperature, and then to leave the residue. Was hot filtered at 200 ° C. to remove the infusible portion at the same temperature to obtain 200 g of a light material removal pitch.

The light content removal pitch was an optically isotropic pitch containing 25% of xylene-insoluble matter.

On the other hand, 180 g of the above-mentioned light content removing pitch was subjected to polycondensation at 400 ° C. for 8 hours under a nitrogen stream while removing the light content produced by the reaction to obtain a heat-treated pitch of 97.2 g.

This heat-treated pitch contains a melting point of 263 ° C, a softening point of 308 ° C, xylene insoluble content of 77%, and quinoline insoluble content of 31%. It was a family compound.

25 g of the organosilicon polymer obtained in Reference Example 1 and 20 ml of xylene were added to 57 g of the light content removal pitch, the temperature was raised with stirring, xylene was distilled off, and the mixture was reacted at 400 ° C. for 4 hours to give 57.4 g of a precursor polymer. (1) was obtained.

As a result of infrared absorption spectrum measurement, this precursor polymer (1) was found to have Si-H bonds (IR: 2100c) present in the organosilicon polymer.
m ^-1 ) decrease and new Si-C (carbon of benzene ring)
The formation of a bond (IR: 1135 cm ^-1 ) was confirmed to indicate that the organosilicon polymer is a copolymer having a part of silicon atoms directly bonded to a polycyclic aromatic ring.

To 57.4 g of the precursor polymer (1), tetraoctoxytitanium [Ti
(OC ₈ H ₁₇ ) ₄ ] 3.87 g xylene solution (25% xylene solution 1
5.5 g) was added, xylene was distilled off, and the mixture was reacted at 340 ° C. for 1 hour to obtain 56 g of a random copolymer (2).

This copolymer did not contain a xylene-insoluble portion, had a weight average molecular weight of 1580, a melting point of 258 ° C and a softening point of 292 ° C.

6.4 g of the random copolymer (2) and 90 g of the mesophase polycyclic aromatic compound are mixed and melt-heated at 380 ° C. for 1 hour in a nitrogen atmosphere to obtain a metal-containing polycyclic aromatic polymer in a uniform state. Obtained.

This polymer had a melting point of 264 ° C., a softening point of 307 ° C., and contained a 68% xylene-insoluble matter.

Using the above-mentioned high molecular weight material as a raw material for spinning, using a metal nozzle having a nozzle diameter of 0.15 mm, melt spinning is performed at 360 ° C., the obtained spinning raw yarn is infusible at 300 ° C. in air, and further an argon atmosphere Firing was performed at 1300 ° C. in the middle to obtain an inorganic fiber having a diameter of 7.5 μm.

This fiber has a tensile strength of 358 Kg / mm ² and a tensile modulus of 32 t / mm ² , and the fracture surface was observed using a scanning electron microscope, and as a result, a coral-like random and radial mixed structure with multiple layers of crystalline layers was observed. Met.

After crushing this inorganic fiber, alkali melting and hydrochloric acid treatment are applied to form an aqueous solution, and then high-frequency plasma emission spectroscopy (IC
As a result of performing P), the silicon content was 0.95% and the titanium content was 0.06%.

Reference Example 6 (Production of Inorganic Fiber V) 39 g of the precursor polymer (1) obtained in Reference Example 5 was added with an ethanol-xylene solution (1.5%) of 5.4 g of tetrakisacetylacetonatozirconium, and xylene and ethanol were distilled off. Then, the mixture was polymerized at 250 ° C. for 1 hour to obtain 39.5 g of a random copolymer (2).

20 g of this polymer and 50 g of the mesophase polycyclic aromatic compound obtained in Reference Example 5 were finely pulverized and mixed, melt-mixed at 360 ° C. for 1 hour, and spun at 350 ° C. using a nozzle having a nozzle diameter of 0.2 mm to obtain The resulting spun raw yarn is made infusible at 250 ° C in air, and further fired at 1400 ° C in an argon atmosphere, and an inorganic fiber V with a diameter of 11μ
Got

The tensile strength of this fiber was 345 kg / mm ² , and the tensile elastic modulus was 35 t / mm ² .

Reference Example 7 (Production of Inorganic Fiber VI) The procedure of Reference Example 5 was repeated except that the amounts of the light content removal pitch and the organosilicon polymer were changed to 60 g and 40 g, respectively.
g of precursor polymer (1) was obtained.

Hafnium chloride 7.2 is added to 40 g of this precursor copolymer (1).
g of ethanol-xylene solution (1.5%) was added, and xylene and ethanol were distilled off, followed by polymerization at 250 ° C. for 1 hour to obtain 43.5 g of a random copolymer (2).

20 g of this polymer and 80 g of the mesophase polycyclic aromatic compound obtained in Reference Example 5 were finely pulverized and mixed, and then melt-mixed at 360 ° C. for 1 hour, melt-spun at 360 ° C. and infusible at 270 ° C., 12.5μ by firing at 1200 ° C in argon
Inorganic fiber VI was obtained.

The tensile strength of this fiber was 335 kg / mm ² , and the tensile elastic modulus was 35 t / mm ² .

Reference Example 8 (Production of Inorganic Fiber VII) 1.8 g of a random copolymer (2) obtained in the same manner as in Reference Example 5
And 90 g of the mesophase polycyclic aromatic compound obtained in the same manner as in Reference Example 5 were melt mixed at 400 ° C. for 1.5 hours under a nitrogen stream,
A spinning dope having a melting point of 265 ° C. and a xylene insoluble content of 55% was obtained.
Using a nozzle with a nozzle diameter of 0.15 mm, this dope was melt-spun at 350 ° C., infusibilized at 300 ° C., and then fired at 1700 ° C. to give a diameter of 8
μ of inorganic fiber was obtained.

After crushing this inorganic fiber, alkali melting and hydrochloric acid treatment are applied to form an aqueous solution, and then high-frequency plasma emission spectroscopy (IC
As a result of performing P), the silicon content is 0.3% and the titanium content is
It was 0.015%.

The tensile strength of this fiber was 335 kg / mm ² , and the tensile elastic modulus was 40 t / mm ² .

Reference Example 9 (Production Method of Si-Ti-C-O Fiber) Polyborosiloxane was added at a ratio of 3 parts to 100 parts of polydimethylsilane synthesized by dechlorinating and condensing dimethyldichlorosilane with sodium metal, and nitrogen was added. A polycarbosilane having a main chain skeleton mainly composed of carbosilane units of the formula (Si—CH ₂ ) and having a hydrogen atom and a methyl group at the silicon atom of the carbosilane units. Prepared. Titanium alkoxide was added to this polycarbosilane and crosslinked in nitrogen at 340 ° C. to obtain a polytitanocarbosilane composed of 100 parts of carbosilane units and 10 parts of titanoxane of the formula (Ti—O). .
This polymer was melt-spun, infusibilized at 190 ° C in air, and then fired at 1300 ° C in nitrogen to give a fiber diameter of 13
An inorganic fiber mainly containing silicon, titanium, carbon and oxygen and having a titanium element content of 3% and having a tensile strength of 310 kg / mm ² and an elastic modulus of 16 t / mm ² (monofilament method) was obtained. The obtained inorganic fibers are amorphous composed of Si, Ti, C and O, and β-Si.
C, TiC, solid solution of β-SiC and TiC and TiC _1-x (however, 0
Si-comprising a mixed system of crystalline ultrafine particles with a particle size of <x <1) of about 50Å and an aggregate of amorphous SiO ₂ and TiO _2.
It was a Ti-CO fiber.

Example 1 Bisphenol A type epoxy resin (XB manufactured by Ciba Geigy)
2879A) and 100 parts of dicyandiamide curing agent (XB2879B manufactured by Ciba-Geigy Co.) were uniformly mixed, and then the mixture was dissolved in a mixed solvent of methyl cellosolve and acetone at a weight ratio of 1: 1 to obtain 28% of the above mixture. A solution was prepared.

After impregnating the inorganic fiber I obtained in Reference Example 2 with the above solution, it was drawn in one direction using a drum winder and heated in a heat circulating oven at 100 ° C. for 14 minutes to draw in one direction in a semi-cured state. An aligned inorganic fiber prepreg sheet was prepared.

In the same way, carbon fiber prepregs that were unidirectionally aligned in a semi-cured state using surface-treated carbon fibers (polyacrylonitrile-based, fiber diameter 7μ, tensile strength 300Kg / mm ² , tensile elastic modulus 24t / mm ² ). Sheets were prepared.

The thus-prepared inorganic fiber I and carbon fiber prepreg sheets were alternately laminated in the same axial direction and then hot pressed to produce a hybrid fiber (inorganic fiber / carbon fiber) reinforced epoxy composite material.

The fiber content of this composite material was 30% by volume of inorganic fibers and 30% by volume of carbon fibers, for a total of 60% by volume.

The tensile strength and the tensile elastic modulus of the obtained composite material in the 0 degree direction are 191 Kg / mm ² and 16.8 t / mm ² , respectively, and the bending strength in the 0 degree direction is 195 Kg / mm ² , and the bending strength in the 90 degree direction is 90 °. Strength is 7.8Kg
/ mm ² , interlayer shear strength 8.8Kg / mm ² , bending impact value 230Kg ・
It was cm / cm ² .

Example 2 Instead of carbon fiber, Si-Ti-CO shown in Reference Example 9 was used.
A hybrid fiber-reinforced epoxy composite material was produced in the same manner as in Example 1 using the fibers. The fiber content of this composite material is 30% by volume of inorganic fibers, 30% by volume of Si-Ti-CO fibers, and 60% by volume in total. The tensile strength and elastic modulus in the 0 degree direction of the obtained composite material are 200 kg / mm ² and 15.9 t / m, respectively.
m ^2, and the bending strength of the 0-degree direction, 215Kg / mm ^2, 90 ° direction bending strength is 12.8 kg / mm ^2, the interlayer shear strength is 12.1 kg / m
The m ² and bending impact value were 282 Kg · cm / cm ² .

Comparative Example 1 Tensile strength 300Kg / mm ² , Tensile modulus 21t / mm ² , Fiber diameter 7.5μ
In the same manner as in Example 1 except that the polyacrylonitrile-based carbon fiber of Example 1 was used, a unidirectionally aligned semi-cured carbon fiber prepreg sheet was prepared.

The prepreg sheets were laminated with the fiber axes being the same, and then hot pressed to produce a carbon fiber reinforced epoxy composite material. The fiber content of this composite material is 60% by volume. The resulting 0-degree direction tensile strength and tensile modulus of the composite material are each 150 Kg / mm ² and 14t / mm ^2, bending strength of the 0 degree direction, 172Kg / mm ^2, 90 ° direction of the flexural strength 6.2
Kg / mm ^2, the interlayer shear strength is 8.1 kg / mm ^2, bending impact value 150Kg
・ It was cm / cm ² .

Comparative Example 2 A Si-Ti-C-O fiber prepreg sheet was prepared in the same manner as in Example 1 using only the Si-Ti-C-O fiber obtained in Reference Example 9 and in the same manner as in Comparative Example 1. , Si-Ti-C-O
A fiber reinforced epoxy composite was produced. The fiber content of this composite material is 60% by volume. The tensile elastic modulus in the 0 ° direction of the obtained composite material was 11.3 t / mm ² . The other mechanical strengths were almost the same values as in Example 2.

Examples 3 to 5 Alumina fibers, silicon carbide fibers or glass fibers having the properties shown in Table 1 (these fibers are referred to as second reinforcing fibers) are used in place of the carbon fibers, and the same as in Example 1. Then, a hybrid fiber reinforced epoxy resin composite material was manufactured. The fiber content of these composite materials was 30% by volume of inorganic fibers and 30% by volume of the second reinforcing fibers, for a total of 60% by volume.

The performance of the obtained hybrid fiber reinforced epoxy resin composite material is shown in Table 2.

Comparative Examples 3 to 5 Using alumina fiber, silicon carbide fiber or glass fiber,
An alumina fiber prepreg sheet, a silicon carbide fiber prepreg sheet and a glass fiber prepreg sheet were prepared in the same manner as in Example 1, and similarly to Comparative Example 1, an alumina fiber reinforced epoxy composite material, a silicon carbide fiber reinforced epoxy composite material and A glass fiber reinforced epoxy composite material was produced. The fiber content of these composite materials was 60% by volume.

The mechanical properties of the obtained composite material are shown in Table 3.

Example 6 As the inorganic fiber, the inorganic fiber II obtained in Reference Example 3 was used, and instead of the carbon fiber, the fiber diameter was 140 μ, and the tensile strength was 350.
A hybrid fiber-reinforced epoxy resin composite material was produced in the same manner as in Example 1 using silicon carbide fibers having a carbon core wire of Kg / mm ² and a tensile elastic modulus of 43 t / mm ² . The fiber content of this composite material was 30% by volume of inorganic fibers and 16% by volume of silicon carbide fibers having carbon as a core wire, for a total of 46% by volume. The obtained composite material has a tensile strength in the 0 degree direction of 168 kg / mm.
² , the tensile elastic modulus in the 0 ° direction was 22 t / mm ² , the bending strength in the 0 ° direction was 213 Kg / mm ^2, and the bending strength in the 90 ° direction was 6.7 Kg / mm ² .

Comparative Example 6 A silicon carbide fiber prepreg sheet having carbon as a core wire was prepared in the same manner as in Example 1 using the silicon carbide fiber having carbon as a core wire used in Example 6, and carbon was prepared as in Comparative Example 1. A silicon carbide fiber reinforced epoxy resin composite material having a core wire of was obtained. The silicon carbide fiber having carbon as a core wire has a large fiber diameter, and thus the fiber content was only 33% by volume.

The obtained composite material has a tensile strength in the 0 ° direction of 140 kg / mm ² ,
Tensile elastic modulus in the 0 degree direction is 23t / mm ² , bending strength in the 0 degree direction is 1
The bending strength was 95 kg / mm ² and the bending strength in the 90 ° direction was 3.1 kg / mm ² .

Example 7 As the inorganic fiber, the inorganic fiber III obtained in Reference Example 4 was used, and instead of the carbon fiber, the fiber diameter was 140 μ, and the tensile strength was 357.
A hybrid fiber-reinforced epoxy resin composite material was produced in the same manner as in Example 1 using boron fibers having a Kg / mm ² and a tensile modulus of 41 t / mm ² . The fiber content of this composite material is 30% by volume of inorganic fibers and 20% by volume of boron fibers, for a total of 50% by volume.
Met.

The obtained composite material has a tensile strength in the 0 degree direction of 178 kg / mm ² ,
The tensile elastic modulus in the 0 ° direction was 21 t / mm ² , the bending strength in the 0 ° direction was 215 kg / mm ^2, and the bending strength in the 90 ° direction was 7.0 kg / mm ² .

Comparative Example 7 A boron fiber prepreg sheet was prepared in the same manner as in Example 1, except that the boron fiber used in Example 7 was used alone, and a boron fiber-reinforced epoxy resin composite material was obtained in the same manner as in Comparative Example 1. The boron fiber had a large fiber diameter, and thus had a fiber content of only 31% by volume. 0 of the obtained composite material
The tensile strength in the 0 ° direction is 154 kg / mm ² , the tensile elastic modulus in the 0 ° direction is 22 t / mm ² , the bending strength in the 0 ° direction is 193 kg / mm ^2, and the bending strength in the 90 ° direction is 3.8 kg / mm ^2. It was

Example 8 Instead of carbon fiber, tensile strength 270 kg / mm ² , tensile modulus 1
A hybrid fiber reinforced epoxy composite material was produced in the same manner as in Example 1 using 3 t / mm ² of aramid fiber. The fiber content of this composite material was 30% by volume of inorganic fibers and 30% by volume of aramid fibers, for a total of 60% by volume. The tensile strength, tensile elastic modulus and bending strength of the obtained composite material in the 0 degree direction are respectively 158 Kg / mm ² , 12 t / mm ² and 161 Kg / mm ^2, which are significantly stronger and more elastic than the aramid fiber reinforced epoxy resin. The aramid fiber reinforced epoxy resin with a fiber content of 60% by volume has a tensile strength in the 0 degree direction, a tensile elastic modulus and a bending strength of 95 Kg / mm ² , 5.3 t / mm ² and 93 Kg / mm ² , respectively. there were.). The bending impact value of the obtained composite material is 272K.
g · cm / cm ² did not significantly reduce the impact resistance characteristic of aramid fibers (the bending impact value of aramid fiber-reinforced epoxy resin with a fiber content of 60% by volume was 302 Kg · c
It was m / cm ² . ).

Example 9 Bisphenol A type epoxy resin (XB manufactured by Ciba Geigy)
2879A) and 100 parts of dicyandiamide curing agent (XB2879B manufactured by Ciba-Geigy Co.) were uniformly mixed, and then the mixture was dissolved in a mixed solvent of methyl cellosolve and acetone at a weight ratio of 1: 1 to obtain 28% of the above mixture. A solution was prepared.

After impregnating the inorganic fiber IV obtained in Reference Example 5 with the above solution, it was drawn in one direction using a drum winder, and heated in a heat circulation oven at 100 ° C. for 14 minutes to draw in one direction in a semi-cured state. An aligned inorganic fiber prepreg sheet was prepared.

In the same way, carbon fiber prepregs that were unidirectionally aligned in a semi-cured state using surface-treated carbon fibers (polyacrylonitrile-based, fiber diameter 7μ, tensile strength 300Kg / mm ² , tensile elastic modulus 24t / mm ² ). Sheets were prepared.

The thus obtained inorganic fiber IV and carbon fiber prepreg sheets were alternately laminated in the same axial direction and then hot pressed to produce a hybrid fiber (inorganic fiber / carbon fiber) reinforced epoxy composite material.

The fiber content of this composite material was 30% by volume of inorganic fibers and 30% by volume of carbon fibers, for a total of 60% by volume.

The tensile strength and tensile elastic modulus of the obtained composite material in the 0 degree direction are 197 Kg / mm ² and 16.8 t / mm ² , respectively, and the bending strength in the 0 degree direction is 199 Kg / mm ² , and the bending strength in the 90 degree direction is 90 °. Strength is 8.0Kg
/ mm ² , interlaminar shear strength is 9.1 kg / mm ² , bending impact value is 235 kg
It was cm / cm ² .

Example 10 Instead of carbon fiber, Si-Ti-CO shown in Reference Example 9 was used.
A hybrid fiber-reinforced epoxy composite material was produced in the same manner as in Example 9 using the fibers. The fiber content of this composite material is 30% by volume of inorganic fibers, 30% by volume of Si-Ti-CO fibers, and 60% by volume in total. The tensile strength and elastic modulus in the 0 degree direction of the obtained composite material are 207 kg / mm ² and 15.9 t / m, respectively.
m ² , the bending strength in the 0 ° direction is 221 kg / mm ² , the bending strength in the 90 ° direction is 13.1 kg / mm ² , the interlaminar shear strength is 12.9 kg / mm ² ,
The bending impact value was 290 kg · cm / cm ² .

Examples 11 to 13 Similar to Example 9, except that alumina fibers, silicon carbide fibers or glass fibers having the properties shown in Table 1 (these fibers are referred to as second reinforcing fibers) were used instead of the carbon fibers. Then, a hybrid fiber reinforced epoxy resin composite material was manufactured. The fiber content of these composite materials was 30% by volume of inorganic fibers and 30% by volume of the second reinforcing fibers, for a total of 60% by volume.

The performance of the obtained hybrid fiber reinforced epoxy resin composite material is shown in Table 4.

Example 14 As the inorganic fiber, the inorganic fiber V obtained in Reference Example 6 was used, and instead of the carbon fiber, the fiber diameter was 140 μ, and the tensile strength was 350.
A hybrid fiber-reinforced epoxy resin composite material was produced in the same manner as in Example 1 using silicon carbide fibers having a carbon core wire of Kg / mm ² and a tensile elastic modulus of 43 t / mm ² . The fiber content of this composite material was 30% by volume of inorganic fibers and 16% by volume of silicon carbide fibers having carbon as a core wire, for a total of 46% by volume.

The obtained composite material has a tensile strength in the 0 ° direction of 171 kg / mm ² ,
The tensile elastic modulus in the 0 ° direction was 22 t / mm ² , the bending strength in the 0 ° direction was 218 kg / mm ^2, and the bending strength in the 90 ° direction was 6.9 kg / mm ² .

Example 15 Inorganic fiber VI as obtained in Reference Example 7 as inorganic fiber
Instead of carbon fiber, using a boron fiber having a fiber diameter of 140μ, a tensile strength of 357 Kg / mm ² , and a tensile elastic modulus of 41 t / mm ² .
A hybrid fiber reinforced epoxy resin composite material was produced in the same manner as in Example 9. The fiber content of this composite material is
The inorganic fibers were 30% by volume, the boron fibers were 20% by volume, and the total was 50% by volume.

The obtained composite material has a tensile strength in the 0 degree direction of 185 kg / mm ² ,
The tensile elastic modulus in the 0 ° direction was 21 t / mm ² , the bending strength in the 0 ° direction was 219 kg / mm ^2, and the bending strength in the 90 ° direction was 7.8 kg / mm ² .

Example 16 The inorganic fiber VII obtained in Reference Example 8 was used as the inorganic fiber, and aramid fiber having a tensile strength of 270 kg / mm ² and a tensile elastic modulus of 13 t / mm ² was used in place of the carbon fiber. A hybrid fiber reinforced epoxy composite material was manufactured in the same manner. The fiber content of this composite material is 30% by volume of inorganic fibers.
Then, the aramid fiber was 30% by volume, and the total amount was 60% by volume.

The tensile strength, tensile modulus and bending strength of the obtained composite material in the direction of 0 degree are 162 kg / mm ² , 16 t / mm ² and 166 kg /, respectively.
mm ^2, which is significantly higher in strength and elastic modulus than the aramid fiber reinforced epoxy resin (tensile strength, tensile elastic modulus and bending strength in the 0 degree direction of the aramid fiber reinforced epoxy resin having a fiber content of 60% by volume are They were 95 kg / mm ² , 5.3 t / mm ² and 93 kg / mm ² , respectively.) Further, the bending impact value of the obtained composite material was 276 kg · cm / cm ² , which did not significantly reduce the impact resistance characteristic of aramid fibers (the aramid fiber reinforced epoxy resin having a fiber content of 60% by volume). The bending impact value of the resin was 302 Kg · cm / cm ^2. )

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Shibuya 5 1978, Kozugushi, Ube City, Yamaguchi Prefecture 5 Ube Kosan Co., Ltd. Ube Research Institute Examiner Hiroyuki Taniguchi

Claims (1)

[Claims] 1. Inorganic fibers and carbon fibers, glass fibers, boron fibers, alumina fibers, silicon nitride fibers, aramid fibers, silicon carbide fibers, carbon-based silicon carbide fibers and Si.
-M-C-O fibers (M represents Ti or Zr), which is a hybrid material with at least one fiber selected from the group consisting of fibers, is used as a reinforcing material, and a plastic composite material having a plastic matrix is used as the inorganic fiber. Is titanium,
An inorganic fiber obtained from a metal-containing polycyclic aromatic polymer containing silicon and at least one element selected from the group consisting of zirconium and hafnium, the constituent components of which are: a) a mesophase constituting the polymer. A carbonaceous material having at least one crystal arrangement state selected from the group consisting of a radial structure derived from a polycyclic aromatic compound in a state, an onion structure, a random structure, a core radial structure, a skin onion structure and a mosaic structure, b) Non-oriented crystalline carbon and / or amorphous carbon derived from an optically isotropic polycyclic aromatic compound containing an organic solvent insoluble component constituting a polymer, and c) Si, M, C and An amorphous substance consisting essentially of O,
And / or substantially β-SiC, MC, a solid solution of β-SiC and MC and MC
_It is an aggregate of crystalline ultrafine particles of _{1-x with} a particle size of 500Å or less and amorphous SiO _y and MO _z. The proportion of constituent elements is Si; 5 to 70% by weight, M; 0.5 to 45% by weight. %,
C: 20-40% by weight and O: 0.01-30% by weight, Si-M-
C—O substance (wherein M is at least one element selected from Ti, Zr and Hf, and 0 <x <1, 0 <y ≦
2, 0 <z ≦ 2. ) Is a hybrid fiber-reinforced plastic composite material.