JPH10121371A - Fiber structure for fiber-reinforced composite material and production of fiber reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber-reinforced composite material different in mechanical or thermal physical properties between the inner part and outer part by subjecting a fiber structure comprising a reinforced fiber and a non-reinforced fiber to physical or chemical treatment before or after impregnating into a matrix resin. SOLUTION: A fiber structure such as a one-way woven fabric or a two-dimensional woven fabric or a three dimensional woven fabric or network-like structure is formed by using a reinforcing fiber such as carbon fiber and a non-reinforcing fiber such as aramid fiber. The fiber structure is subjected to high temperature heating treatment before or after impregnating into a matrix resin such as phenol resin and the aramid fiber as the non-reinforcing fiber is substantially decomposed to provide the objective carbon/carbon composite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fiber structure for a fiber-reinforced composite material and a method for producing the fiber-reinforced composite material.

[0002]

2. Description of the Related Art Fiber-reinforced composite materials are not only excellent in strength characteristics such as high strength and high elastic modulus, but also lightweight.
It is known as an industrial material having excellent thermal characteristics, such as being capable of increasing the thermal conductivity and decreasing the coefficient of thermal expansion. However, the conventional fiber reinforced composite material is a material in which the number of fiber axes of the woven fabric is kept constant, and is not a material that changes the woven structure between the inner surface and the outer surface of the fiber reinforced composite material. Therefore, the strength and thermal characteristics did not change between the inside and the outside surface of the fiber reinforced composite material, and the physical properties were uniform. For this reason, when performing joining with dissimilar materials, the coefficient of thermal expansion is often too low or the elastic modulus is too high, so that joining with sufficient strength characteristics is impossible, or near the surface In most cases, it is difficult to make the thermal conductivity in a certain direction higher than a desired value.
Further, the conventional unidirectional fiber reinforced composite material requires a great deal of labor to align fibers in one direction, and it has been difficult to produce a unidirectional fiber reinforced composite material having a uniform fiber content.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to remedy the disadvantages of the above-mentioned conventional fiber-reinforced composite materials. And to provide a method for producing a fiber-reinforced composite material having different mechanical and thermal properties between the inside and the outside surface of the fiber-reinforced composite material. A further object of the present invention is to improve the disadvantages of producing the above-mentioned conventional unidirectional fiber-reinforced composite material, and in particular to provide a simple and inexpensive method for producing a unidirectional fiber-reinforced composite material. is there.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a fibrous structure integrally constituted by reinforced fibers and non-reinforced fibers is subjected to physical treatment or chemical treatment to substantially remove or modify the non-reinforced fibers. The present invention relates to a method for producing a fiber structure for a fiber-reinforced composite material, wherein Furthermore, the present invention provides a physical treatment or a chemical treatment before or after impregnating the matrix into the fibrous structure integrally constituted by the reinforcing fibers and the non-reinforced fibers to substantially reduce the non-reinforced fibers. The present invention relates to a method for producing a fiber-reinforced composite material, which is characterized by being removed or modified.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A fiber structure according to the present invention is a unidirectional woven fabric, a two-dimensional woven fabric, a three-dimensional woven fabric or a mesh-like fabric for producing a substantial UD material in which a weft is sparsely knitted with respect to a warp. It is a structure. A three-dimensional woven fabric is a woven fabric three-dimensionally woven only with reinforced fibers or reinforced fibers and non-reinforced fibers, and has a uniaxial weave such as a braid, a biaxial weave, or a three-dimensional weave according to the number of fiber axes constituting the woven fabric. Shaft weave includes three-dimensional fabrics woven with four or more axes of fibers. What is a two-dimensional fabric?
A woven fabric which is woven substantially in a plane by only the reinforcing fibers or the reinforced fibers and the non-reinforced fibers, and is woven by uniaxial weaving, biaxial weaving, and triaxial or more fibers according to the number of fiber axes constituting the woven fabric. Includes two-dimensional fabrics.

In the present invention, in addition to the woven fabric, a reinforcing fiber is laminated in a double-girder shape from the direction of two fiber axes or three or more fiber axes and the intersection is fused with a thermoplastic resin or the like to form a mesh-like fabric. Structures can also be used. The present invention typically employs any two or more of three types of woven fabrics having different numbers of axes, such as three-dimensional or two-dimensionally woven triaxial fiber woven fabric, biaxial fiber woven fabric, and one-axis fiber woven fabric. Are combined in the same material, and mechanical and thermal properties in the same material,
In some cases, the present invention provides a method for producing a fiber reinforced composite material or a woven fabric for a fiber reinforced composite material in which the electromagnetic properties can be changed at a specific portion of the material. It is preferable that the fibers of at least one fiber axis are continuous and integrally reinforced. This plays a role in mitigating a remarkable change in physical properties due to an interface existing in the same material.

[0007] The physical treatment or the chemical treatment in the present invention is a treatment capable of substantially removing or modifying non-reinforced fibers while maintaining the shape and material properties of the reinforced fibers substantially stably by the treatment. Say. Specifically, heat treatment such as carbonization treatment and heat treatment, combustion, oxidation treatment with an oxidizing agent, etc., reduction treatment with a reducing agent, acid treatment with sulfuric acid, nitric acid, etc., alkali treatment with sodium hydroxide, potassium hydroxide, etc. Examples of the method include a solvent treatment such as a solubilization treatment and an electric treatment such as an electrolytic treatment. Further, in order to promote these physical and chemical treatments, ultrasonic treatment and treatments such as heating, cooling, pressurizing, and depressurizing can be combined.

[0008] Substantially removing or modifying the non-reinforced fibers means that 50% by weight or more, preferably 60% by weight or more, more preferably 80% by weight or more of the components constituting the fibers are thermally, chemically decomposed, carbonized, heat-treated, or the like. Means that the non-reinforced fiber itself does not exhibit some or all of the physical or quantitative properties of the material inherently provided before the treatment, which means that the non-reinforced fiber itself is inferior to others in terms of functional expression. The reinforcing fiber used in the present invention is a fiber that is not substantially modified or removed by a physical treatment or a chemical treatment, and is preferably a fiber that does not substantially change the material properties of the fiber by the treatment.

The fibers which are not substantially modified or removed by a physical treatment or a chemical treatment as the reinforcing fibers used in the present invention are usually 50 wt% of the components constituting the fibers.
Amount, preferably 80 wt% or more, more preferably 90 wt% or more remains without being removed or denatured by thermal or chemical decomposition, and the reinforcing fibers themselves exhibit the material properties originally provided before the treatment. Means such fibers.
The interval between the reinforcing fiber bundles to be arranged is 0 to 100 mm, preferably 0 to 10 mm, and twisting and untwisting may be added.
It may be non-twisted. The number of twists is 0.1 to 20 times / m, and in the case of non-twist, an opened fiber can be used.
The reinforcing fiber diameter is usually 4 to 30 μm, preferably 6 to 15 μm.
m and 100-100,000, preferably 500
Up to 30,000 reinforcing fibers can be bundled and used, and a sizing agent can be used for the reinforcing fibers. Specific reinforcing fibers include organic fibers, ceramic fibers, carbon fibers, metal fibers, and the like, but the fibers selected vary depending on the combination with the treatment used. Examples of the organic fiber include a nylon fiber, a polyacrylonitrile fiber, an aramid fiber, a polyethylene fiber, a Teflon fiber, and the like. These fibers are hardly removed or modified by electrolytic treatment, acid treatment, or the like. Examples of the ceramic fiber include silicon carbide fiber, alumina fiber, glass fiber, titanium carbide fiber, boron nitride fiber, and the like.
These fibers are not easily removed or modified by acid treatment, oxidation treatment or the like. Examples of the carbon fibers include petroleum pitch-based, coal pitch-based, polyacrylonitrile-based, and rayon-based carbon fibers, or infusible fibers and precursor carbonized fibers thereof, and all-carbonized fibers. Hardly removed or denatured by treatment or carbonization.

Various types of metal fibers can be used, for example, stainless steel fiber, copper fiber, aluminum fiber, nickel fiber, titanium fiber, tungsten fiber, and the like. These fibers are subjected to heat treatment such as combustion and carbonization. Hardly removed or denatured. Depending on the treatment used, any of these fibers can be used as the reinforcing fiber, but among them, it is lightweight and relatively stable to chemical and physical treatments, and also has a thermal conductivity and an elastic modulus. Excellent carbon fibers are preferred. Two, three, or more types of reinforcing fibers can be combined. In this case, a specific portion of the material may be independently combined with a different type of reinforcing fiber from the other portions.

The non-reinforced fiber used in the present invention is a fiber that is substantially modified or removed by a physical treatment or a chemical treatment, and is preferably a fiber whose material properties are substantially changed by the treatment. . The non-reinforced fiber is preferably a fiber that is easily woven with the reinforcing fiber, and usually has a tensile strength of preferably 10 MPa to 10 GPa, more preferably 40 MPa to 10 GPa, still more preferably 50 HPa to 10 GPa, and most preferably 100 MPa to 10 GPa.
Mpa to 8 GPa can be used. The non-reinforced fiber usually has a fiber diameter of 4 to 30 μm, preferably 6 to 1 μm.
1 to 10,000 of 5 μm, preferably 500 to
5000 bundles can be used, and the diameter of the fiber bundle is usually 4 to 5
000 μm, preferably 500 to 2500 μm. The interval at which the non-reinforced fibers are arranged may be any interval at which the reinforcing fibers can be stably fixed by the non-reinforced fibers and the matrix can be easily impregnated, and is preferably 0 to 200 mm, more preferably 0 to 50 mm. If the weft spacing is less than the above range, the matrix impregnation property will be reduced, and a sufficient reinforcing effect will not be obtained.If the weft spacing exceeds the above range, the retention of the reinforcing fibers will be reduced and workability during production will be reduced. It is not preferable. The non-reinforced fibers may be substantially removed or denatured by the above treatment, so that the function as the fibers may be significantly changed, and it is not always necessary to remove all of them. However, the residual ratio of the fibers is usually 50 wt% or less. , Preferably 40 wt% or less,
More preferably, it is at most 20 wt%. Specific non-reinforced fibers include organic fibers, carbon fibers, metal fibers and the like, but the fibers selected by the treatment are different. Usually, fibers belonging to a type different from the reinforcing fibers can be selected as the non-reinforced fibers. For example, when the reinforcing fibers are carbon fibers, organic fibers and metal fibers can be selected as the non-reinforced fibers (see Table 1).

Examples of the organic fibers include synthetic fibers such as nylon fibers, polyacrylonitrile fibers, aramid fibers, and polyethylene fibers, and natural fibers such as cotton yarns and silk yarns, and combinations thereof. These fibers are decomposed by acid treatment. It is easily burned away or carbonized by removal or thermal treatment. Examples of the carbon fiber include petroleum pitch-based, coal pitch-based, polyacrylonitrile-based or rayon-based carbon fibers or infusible fibers or precursor carbonized fibers that are precursor fibers thereof, and these fibers are oxidized. It is easily removed or denatured by treatment. As the metal fiber, various things can be mentioned, for example, aluminum fiber, nickel fiber,
Examples thereof include iron fibers, zinc fibers, and copper fibers. These fibers are easily removed or modified by an acid or alkali treatment.

As the non-reinforced fibers, any of these fibers can be used depending on the combination with the above-mentioned treatment to be used, but organic fibers are most preferred. As an effect, for example, when manufacturing an inorganic fiber reinforced composite material having different physical properties between the inside and the outside surface of the fiber reinforced composite material by performing heat treatment using carbon fiber as the reinforcing fiber and aramid fiber as the non-reinforced fiber, The effect of adding a shape retention property by enabling weaving as a fiber constituting the woven fabric, the effect of adding a matrix spill prevention function when impregnating the matrix until the aramid fiber is decomposed by heat treatment at 800 ° C. or more, the aramid fiber Does not substantially function as a reinforcing fiber after being decomposed by the heat treatment, and has an effect that the material hardly contributes to the mechanical, thermal, and electromagnetic properties of the material. When organic fibers are used as non-reinforced fibers, the decomposition temperature involved in thermal decomposition, the effect of the residue on the physical properties of the fiber-reinforced composite material differs depending on the type, and the resistance of organic fibers due to chemical treatment such as acid treatment also differs. Depending on the type of matrix used for the fiber-reinforced composite material, physical or chemical treatment conditions, heat history during production, etc., the type of organic fiber can be properly selected.

When weaving these non-reinforced fibers with reinforcing fibers, the three-dimensional woven fabric and the two-dimensional woven fabric are mainly made of reinforcing fibers, and a part of the fiber group belonging to a specific fiber axis of the woven fabric is partially replaced with the non-reinforced fibers. And conversely, a non-reinforced fiber as a main component and a reinforced fiber and a woven fabric can also be used. As a specific combination of the reinforcing fiber and the non-reinforced fiber, for example, a carbon fiber is used as the reinforcing fiber, a carbon fiber-modified organic fiber is used as the non-reinforced fiber, a ceramic fiber is used as the reinforcing fiber, and the non-reinforced fiber is oxidized and removed. Combination using possible carbon fiber, using carbon fiber as reinforcing fiber, using metal fiber decomposable by acid as non-reinforced fiber, using metal fiber as reinforcing fiber, and carbonizing and denaturable organic fiber as non-reinforced fiber Combinations to be used are given. Table 1 shows a preferred combination example.

[0015]

[Table 1]

In the case of a planar or sheet-like fibrous structure such as a unidirectional material or a two-dimensional woven fabric, a prepreg impregnated with a matrix resin, preferably a matrix resin such as a thermoplastic resin or a thermosetting resin, is laminated. Subsequent or laminating without impregnating the matrix resin and curing the matrix resin with or without heat treatment after impregnating the matrix resin, and substantially removing the non-reinforced fibers by further performing physical or chemical treatment Alternatively, the desired fiber-reinforced composite material can be obtained by modification. The weave of the one-way material and the two-dimensional fabric may be any weave, specifically, a plain weave, a twill weave, a satin weave, or the like.

The fiber structure for a fiber-reinforced composite material or the fiber-reinforced composite material of the present invention is usually preferably formed of long fibers having a length of 10 mm or more, but short fibers may be mixed with long fibers. In addition, a two-dimensional woven fabric or a laminate of a network structure may be formed by laminating a nonwoven fabric such as a felt. In the present invention, a specific part of the material can be composed of unreinforced fibers and reinforced fibers, the range of which depends on the size of the material itself, but the lower limit of the thickness of the range is usually 0.2 cm or more, preferably 2 cm or more, more preferably 20 cm or more, and the upper limit is not particularly limited, but is usually 100 cm or less, preferably 5 cm or less.
0 cm or less. Further, the interface at which the number of fiber axes of the reinforcing fibers constituting the fiber structure changes can have any shape and may be flat or curved.

The inside of the fibrous structure or the fiber-reinforced composite material of the present invention refers to all material portions of a three-dimensional space having a desired shape selected from the materials. The fiber-reinforced composite material in the present invention is, for example, a three-dimensional three-axis fiber-reinforced composite material or a three-dimensional two-axis fiber-reinforced composite material inside,
While the inside of the material has the excellent mechanical and thermal properties of the conventional fiber-reinforced composite material, the vicinity of the desired outer surface of the material uses a different fiber-reinforced method from the inside as a three-dimensional uniaxial fiber-reinforced composite material. This makes it possible to obtain a composite material having physical properties different from the internal mechanical properties and thermal properties, and integrally formed with different numbers of fiber axes of the reinforcing fibers.

The elements constituting the fiber-reinforced composite material are mainly a reinforcing fiber and a matrix. The matrix is indispensable for constituting the fiber-reinforced composite material, and plays a role of binding or fixing the fibers to each other. The effect on the composite material is not small.
The matrix is not particularly limited as long as it is used for a well-known fiber-reinforced composite material, but a matrix that is not essentially removed or modified by the physical or chemical treatment of the present invention is preferable. Examples are organics, ceramics,
Examples include carbon and metal.

As the organic substance, a thermoplastic resin, a thermosetting resin, or the like can be used. Specifically, epoxy resin, phenol resin, furan resin, urea resin, nylon resin, petroleum pitch, coal tar pitch, Synthetic pitch and the like can be mentioned. Examples of the ceramics include silicon carbide, silicon nitride, boron carbide, boron nitride, alumina, yttria, zirconia, and mullite. Examples of the metal include metals such as copper, aluminum, niobium, tungsten, nickel, and titanium; alloys such as copper, brass, and stainless steel; and intermetallic compounds such as titanium aluminum and niobium aluminum. It is known that the carbon is not only stable to chemical and physical treatments but also easily oriented as a matrix in substantially the same direction as the orientation direction of the fiber, and greatly contributes to the development of physical properties of the fiber-reinforced composite material. And carbon is the most preferred matrix material.

The carbon has various properties depending on the production method. Thermal decomposition of organic substances is roughly classified into two types, one of which is due to thermal decomposition of a thermosetting resin, specifically, the one due to thermal decomposition of a phenol resin, a furan resin or the like. The other is based on the thermal decomposition of a thermoplastic resin, and specifically includes those based on the thermal decomposition of petroleum pitch, coal pitch, and the like. Further, a method by vapor deposition is also effective, and specific examples include a method by vapor deposition of methane, propane, butane, carbon tetrachloride, benzene, or the like.

As described above, as the matrix constituting the fiber-reinforced composite material of the present invention, many types can be mentioned, and any of them is effective. These matrices can be used alone or in combination of two or more. In the present invention, since it is easy to control the orientation of the reinforcing fibers, it is preferable to perform a physical or chemical treatment after impregnating the fiber structure with the matrix, but if the matrix is unstable with respect to the treatment, the fiber The matrix may be impregnated after the structure has been pretreated. By physically or chemically treating the woven fabric according to the present invention to substantially remove or modify the non-reinforced fibers, mechanical properties and thermal properties, and in some cases, electromagnetic properties in the same material can be improved. Can be varied between the interior and exterior surfaces of the device.

The fiber-reinforced composite material of the present invention can be more specifically manufactured by the method described below. By impregnating the matrix into a three-dimensional woven fabric integrally woven with reinforced fibers and non-reinforced fibers, and then physically or chemically treating the non-reinforced fibers, for example, One or more of the outer surfaces as shown in FIG. 1 are made of a unidirectional material, a three-dimensional uniaxial fabric or a three-dimensional biaxial fabric, which is substantially three-dimensionally assembled, and the interior is a three-dimensional triaxial fabric. Alternatively, it is possible to obtain a fiber reinforced composite material which is integrally formed of a woven fabric having three or more four axes and whose physical properties are changed by the difference in the structure of the fiber. Further, the two-dimensional woven fabric integrally woven with the reinforcing fibers and the non-reinforced fibers is laminated and impregnated with the matrix, and then physically or chemically treated to substantially remove or modify the non-reinforced fibers. By doing so, for example, at least one of the outer surfaces, substantially composed of a unidirectional laminate,
It is also possible to obtain a fiber reinforced composite material in which the inside is integrally formed of a two-dimensional biaxial woven fabric or a two-dimensional triaxial woven fabric laminate, and the physical properties of which are changed by the difference in the fiber configuration.

Further, the non-reinforced fibers are substantially treated by physical treatment or chemical treatment after laminating a network-like structure integrally constituted by reinforced fibers and non-reinforced fibers and impregnating the matrix. By removing or denaturing, for example, any one of the external surfaces
The surface or more consists essentially of a unidirectional laminate, the interior of which is 2
It is also possible to obtain a fiber reinforced composite material which is integrally formed of a woven fabric laminate of a framed fabric or a triaxial fabric, and whose physical properties are changed by the difference in the fiber configuration. As a result, the fiber-reinforced composite material obtained according to the present invention not only significantly improves the bondability with dissimilar materials that could not be obtained with the conventional fiber-reinforced composite material, but also selects the desired direction in terms of heat conduction. It is possible to use a material capable of obtaining a high thermal conductivity. When laminating the two-dimensional fabrics, it is also possible to perform a bonding process between the laminated fabrics by performing a needle punching process, a jet flow process, or the like.

The fiber-reinforced composite material composed of the woven fabric
Reinforced fiber volume content (V_f) Indicates the direction of each fiber axis.
Each can have a different value. For example,
The inside of the material is a three-dimensional three-axis orthogonal fiber reinforced composite material (hereinafter referred to as 3
D-3A), and one of the outer surfaces of the material is actually
Qualitatively three-dimensional uniaxial fiber reinforced composite material (hereinafter referred to as 3D-1A part)
3D-3A part and 3D-1A part
In the case of a physically reinforced fiber reinforced composite material, 3D-3
Part A V_fIs the three fiber axis of X fiber axis, Y fiber axis and Z fiber axis
0.1-96% in each direction, preferably 1-70%,
More preferably, 3 to 60% is appropriate, and 3D-1A
Part V_fIs 0.1 to 96, preferably 10 to 90%,
More preferably, 10% to 70% is appropriate. in this case,
3D-3A part X fiber axis, Y fiber axis, Z fiber axis
Axial V _fNeed not be the same,
It is normal to take a standing value, but V in three directions_fSum of values
The total is usually 96% or less, preferably 80% or less,
Preferably, 70% or less is appropriate.

According to the present invention, the physical properties of the fiber-reinforced composite material can be changed between the inside and the outside of the same material, but the physical properties include mechanical properties, thermal properties, and electromagnetic properties. There are physical properties. The mechanical properties include, for example, tensile strength, tensile modulus, compressive strength, compressive modulus, hardness, interlaminar shear strength, Charpy impact strength, impact strength during rapid cooling and rapid heating, and the like. Examples of thermophysical properties include thermal conductivity, thermal expansion coefficient, and heat capacity. Examples of the electromagnetic properties include electrical resistivity, magnetic resistivity, magnetic susceptibility, and dielectric constant. The material properties of the fiber-reinforced composite material according to the present invention can be individually changed depending on the application.

A preferred example of changing the physical properties is a three-dimensional three-axis orthogonal fiber reinforced composite material (hereinafter referred to as 3D-3A) in which the inside of the material is constituted by the X fiber axis direction, the Y fiber axis direction, and the Z fiber axis direction. Portion), and one surface of the outer surface of the material is a three-dimensional uniaxial fiber reinforced composite material (hereinafter, referred to as a 3D-1A portion) in which the reinforcing fiber in the X fiber axis direction of the 3D-3A portion is continuous. The value of the thermal conductivity in the case of the fiber-reinforced composite material in which the 3D-3A portion and the 3D-1A portion are integrally formed is 1 to 12 in the X fiber axis direction of the 3D-3A portion near room temperature.
00W / m · K, preferably 10 to 1200W / m ·
K, more preferably 100 to 1200 W / m · K, and 1 to 1000 W / m · K, preferably 10 to 800 W / m · K, more preferably 20 in the Y fiber axis direction.
Take a value of ~ 700 W / m · K, and 1-1 in the Z fiber axis direction.
000 W / m · K, preferably 10-800 W / m ·
K, more preferably 20 to 700 W / m · K, while the 3D-1A portion is 10 to 1500 W / m · K, preferably 10 to 1 W / m · K in the X fiber axis direction which is the fiber reinforcing direction.
200 W / m · K, more preferably 100 to 1200
It can take the value of W / m · K.

As another example, the same 3D-3A unit as described above
Thermal expansion in case of fiber reinforced composite material consisting of 3D-1A part
In the 3D-3A part, the coefficient is in the X fiber axis direction near room temperature,
0.01 × 10, almost the same in the fiber axis direction and Z fiber axis direction
^-6~ 20 × 10^-6° C^-1, Preferably 0.01 × 10^-6~
15 × 10^-6° C^-1, More preferably 0.05 × 10 ^-6
~ 12 × 10^-6° C^-1And the room temperature in the 3D-1A section
Near X fiber axis direction, Y fiber axis direction, Z fiber axis direction
Is different, and 0.01 × 10^-6~ 5 × 10
^-6° C^-1, Preferably 0.01 × 10^-6~ 4 × 10
^-6° C^-1, More preferably 0.1 × 10^-6~ 4 × 10^-6
° C^-1And the value of 0.1 in the Y fiber axis direction and the Z fiber axis direction.
× 10^-6~ 25 × 10^-6° C^-1, Preferably 1 × 10^-6~
20 × 10^-6° C ^-1, More preferably 2 × 10^-6-10
× 10^-6° C^-1Take the value of As still another example, the same as above
Fiber reinforced composite consisting of 3D-3A part and 3D-1A part
The coefficient of thermal expansion of the material is around room temperature in the 3D-3A part
X axis direction, Y fiber axis direction, Z fiber axis direction
Takes the value of 5 to 300 GPa in the same way,
In the X fiber axis direction, Y fiber axis direction, and Z fiber axis direction around temperature
X-fiber axis direction 50-300 GPa, Y fiber
It takes a value of 1 to 100 GPa in the axial direction and the Z fiber axis direction.

[0029]

As a result of the present invention, the fiber reinforced dimensions are changed between the inside and the outside surface of the fiber reinforced composite material, and the fiber reinforced composite material has different mechanical and thermal properties between the inside and the outside surface. A one-way fiber reinforced composite material can be provided by a fiber reinforced composite material having different mechanical and thermal physical properties between the inner and outer surfaces of the composite material or a simple and inexpensive manufacturing method. The fiber-reinforced composite material obtained according to the present invention is used as an aerospace material, a heat-resistant material, and the like, and has various shapes such as a plate shape, a column shape, a rod shape, a tubular shape, a T shape, an I shape, and a honeycomb shape. Can be

[0030]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Example 1) Tensile modulus of elasticity 40 × 10 ³ kgf /
with fiber diameter 10 micron pitch-based carbon fiber is mm ² as 3000 in the bundle, each space vector 9
It is arranged and arranged in three directions of X, Y, Z different by 0 degree,
Fabric size X fiber axis direction 70mm x Y fiber axis direction 70m
It was woven into a rectangular parallelepiped shape of 500 mm in the mxZ fiber axis direction. At this time, for two planes formed by the Y fiber axis direction and the Z fiber axis direction, the pitch-based carbon fibers in the Y fiber axis direction and the Z fiber axis direction are replaced in a spatial range of 15 mm from the outer surface. Were woven so that only the outer surface portion had carbon fibers only in the X fiber axis direction. The fiber volume content _Vf of the completed woven fabric is V _{fx
= 30%, V fY = 12} %, was V _fZ = 12%. The woven fabric was impregnated with a phenol resin dissolved in an ethanol solution, and vacuum drying was repeated 10 times. Thereafter, the mixture was heated and carbonized at 1000 ° C. in a nitrogen atmosphere at normal pressure, and graphitized and fired at 2500 ° C. Impregnation of this phenolic resin, heating carbonization firing,
Graphitization firing was repeated eight times to produce an integrally molded C / C composite. In the obtained C / C composite, the coefficient of thermal expansion in the Y fiber axis direction near the inner central portion composed of a triaxial woven fabric is 0.5 × 10 ⁻⁶ ° C. ^-1 near room temperature, and is composed of a uniaxial woven fabric. The coefficient of thermal expansion in the Y fiber axis direction of the outer surface thus determined was 4.0 × 10 ⁻⁶ ° C. ^-1 near room temperature.

(Example 2) Si having a fiber diameter of 15 microns
Using C fibers as a bundle of 1,000 fibers,
Are arranged and arranged in two directions, X and Y, which differ by 90 degrees.
Object size X fiber axis direction 300mm x Y fiber axis direction 300
mm plain weave shape. At this time, the Y fiber axial end
A flat area within a range of 20 mm from the external surface
Regarding the area, SiC fibers in the Y fiber axis direction are
Of polyacrylonitrile-based carbon fiber
Only the surface of the part has SiC fibers in the X fiber axis direction only.
Weaved so that Metallic copper on the finished fabric surface
Electroless plating for 20 microns, and laminating 30 sheets,
Vacuum hot press molding at 900 ° C, 30mm thick 2
One-dimensional fiber reinforced copper was obtained. The obtained fiber reinforced copper was placed in oxygen 6
Heat treatment at 00 ° C to burn carbon fibers on the outer surface
Textiles that are integrally composed of two-dimensional woven fabric laminate
Wei-enhanced copper was obtained. Biaxial of the obtained fiber reinforced copper
Axial direction of Y-fiber near the inner center made of woven laminate
Thermal expansion coefficient is 4.5 × 10 around room temperature^-6° C^-1, One axis
Heat in the Y-fiber axial direction on the outer surface composed of a woven laminate
Expansion coefficient is 11.0 × 10 around room temperature ^-6° C^-1Met.

Example 3 Tensile modulus of elasticity 70 × 10 ³ kgf /
with fiber diameter 10 micron pitch-based carbon fiber is mm ² as 9,000 bundle, is located arranged in the X fiber axis direction, the space vector with respect to the X fiber axis 90
Tensile modulus of elasticity 25 × 10 ³ k in two directions of X and Z that differ by degrees
A polyacrylonitrile (PAN) -based carbon fiber having a gf / mm ² fiber diameter of 7 μm is arranged and arranged as a bundle of 6000 fibers, and the fabric size X 1000 in the fiber axial direction.
mm × Y fiber axis direction 100 mm × Z fiber axis direction 500 m
m in a rectangular parallelepiped shape. At this time, the X fiber axis direction 10
00mm, two 20mm widths at both ends and 4mm from the end
80 mm to 520 mm position, ie, 40 mm at the center
The width of the space is woven using cotton yarn of the same bundle thickness in place of the PAN-based carbon fiber in the Y fiber axis direction and the Z fiber axis direction. Weave only to have. The fiber volume content _Vf of the finished woven fabric is _{VfxX for} each fiber axis direction.
= 40%, V _fY = 10%, V _fZ = 8%. From a fiber reinforced composite material obtained by impregnating a melted petroleum pitch into the woven fabric, a cotton thread having a hydroxyl group is hydrolyzed and removed at 70 ° C. using an 80 mol% concentrated sulfuric acid solution, and the triaxial reinforced portion and the uniaxial reinforced material are removed. The fiber reinforced composite material was integrally formed with the portion.

After this, 1000 kgf / cm ²
Baking by heating at 800 ° C in a high-pressure argon atmosphere
It was graphitized and fired at 500 ° C. This pitch impregnation, heating carbonization firing, and graphitization firing were repeated five times to produce a C / C composite. The obtained C / C composite is composed of a uniaxial woven fabric at 1000 mm in the X-fiber axial direction and two places of 20 mm width at both ends and 480 mm to 520 mm from the end, that is, one place in the space of 40 mm width at the center. The other part was a C / C composite composed of a triaxial woven fabric. The resulting C /
Among the 1000 mm in the X fiber axis direction of the C composite, a position 480 mm to 520 mm from the end, that is, 4 at the center.
The C / C composite is bisected at the center position of 0 mm width, that is, 500 mm from the end, and both ends are 20 mm.
Is a uniaxial fiber reinforced C / C composite, and the central part 460 mm is a triaxial fiber reinforced C / C composite.
X fiber axis direction 500mm × Y fiber axis direction 100mm × Z
Two pieces were obtained in a rectangular parallelepiped shape with a fiber axis direction of 500 mm. This 2
The thermal conductivity in the X fiber axis direction near the center of the interior of each C / C composite is 600 W / m · K near room temperature, and the thermal conductivity in the X fiber axis direction on the outer surface is 800 W / m · K near room temperature.
It was K.

Example 4 Pitch-based carbon fiber 15,000
Zero warp was bundled to form a warp, and the warp was arranged without gaps.
Next, a mixed yarn of hot melt fiber and silk having a melting point of 80 ° C. was used as a weft and woven into a warp at a weft interval of 10 mm to prepare a sheet in which carbon fibers were arranged in one direction in a basis weight of 250 g / m ² . After impregnating the sheet with a phenol resin, ten sheets were laminated to produce a laminated structure. 2 ° C / min from room temperature to 1000 ° C
To substantially modify the weft to obtain a fiber reinforced composite material for unidirectional fiber reinforced composite material as a preform for fiber reinforced metal.

Example 5 Pitch-based carbon fiber 12,000
Zero warp was bundled to form a warp, and the warp was arranged without gaps.
Next, a mixed yarn of hot melt fiber having a melting point of 80 ° C. and silk was used as a weft and woven into a warp at a weft interval of 10 mm to produce a sheet in which carbon fibers were arranged in one direction in a basis weight of 200 g / m ² . After forty sheets of this sheet were laminated and fixed with a jig, a petroleum pitch was impregnated to produce a laminated structure. The laminated structure was heat-treated from room temperature to 800 ° C. at 5 ° C./min to substantially modify the weft to obtain a fiber structure for unidirectional fiber reinforced composite material as a preform for C / C composite. This fiber structure was further subjected to pitch impregnation, heating carbonization firing, and graphitization firing three times to obtain a C / C
A composite was made.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a fiber-reinforced form of a fiber-reinforced composite material obtained as a result of the present invention.

FIG. 2 is a laminated cross-sectional view of a unidirectional fiber structure in which reinforcing fibers are used as warps and non-reinforced fibers are used as wefts.

[Explanation of symbols]

 1: Warp (reinforced fiber bundle) 2: Weft (non-reinforced fiber bundle)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI D06M 15/41 B29C 67/14 X // B29K 105: 08

Claims (2)

[Claims] 1. A fiber, wherein a physical structure or a chemical treatment is performed on a fibrous structure integrally constituted by a reinforced fiber and a non-reinforced fiber to substantially remove or modify the non-reinforced fiber. A method for producing a fiber structure for a reinforced composite material. 2. The non-reinforced fiber is substantially treated by a physical treatment or a chemical treatment before or after the impregnation of the matrix into the fiber structure integrally constituted by the reinforcing fiber and the non-reinforced fiber. A method for producing a fiber-reinforced composite material, comprising: