JP2003020542A - Carbon fiber fabric, method for molding using the same, carbon fiber-reinforced plastic and aircraft structural member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive carbon fiber fabric of high productivity capable of giving CFRP( carbon fiber-reinforced plastics) with high toughness and reliability, to provide a method for molding using the fabric, to provide carbon fiber-reinforced plastics, and to provide an aircraft structural member. SOLUTION: This carbon fiber fabric is characterized in that the filament number of the carbon fiber tow is >12,000 but <24,000, the tensile modulus of the carbon fiber is >280 GPa but <500 GPa, and the carbon fiber multifilament >=53 MJ/m<3> in fracture strain energy constitutes this fabric.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carbon fiber cloth used for molding a fiber reinforced plastic (hereinafter sometimes referred to as FRP), and more specifically to a carbon fiber reinforced plastic (hereinafter sometimes referred to as CFRP). The present invention relates to a carbon fiber cloth used for molding, a molding method thereof, and an aircraft structural member made of CFRP.

[0002]

2. Description of the Related Art Recently, the development of super jumbo aircraft and the development of subsonic aircraft have been announced rapidly, and commercial aircraft are also undergoing major changes. The technical challenges of the materials and structural materials of these innovative machines are the satisfactorily satisfying mechanical properties, epoch-making weight reduction and thorough cost reduction. For example, it is necessary to change the material to the primary structural material which has not been used CFRP until now. By the way, the fiber-reinforced plastic made of continuous carbon fibers has excellent mechanical properties in the fiber axis direction, but the mechanical properties sharply decrease with distance from the fiber axis. As a countermeasure against this, for example, a unidirectional prepreg in which fibers are arranged in parallel in one direction and preliminarily impregnated with a matrix resin so that the mechanical properties become a pseudo-isotropic base material, and the fiber axis direction is the length of the FRP molded body. (0
The prepregs are laminated and formed so that they are oriented in the (.degree.) Direction, the width (90.degree.) Direction, and the oblique -45.degree. Direction and + 45.degree. Direction. However, the structural materials of the aircraft are partially affected by the scattering of pebbles on the main wing and tail of the aircraft during gliding, the collision of birds on the wing, and the dropping of tools onto the upper surface of the wing during assembly and repair of the aircraft. Shock may be applied. When such an impact is applied in the thickness direction of the CFRP plate on which the carbon fiber sheet is laminated, the carbon fiber is broken by the impact and a crack is generated between the layers of the CFRP plate to absorb the impact energy. To be done. At this time, if the absorption of the impact energy due to the destruction of the carbon fibers is small, the cracks generated between the layers become large. When a compressive force acts on such a CFRP plate from which the layers are separated, cracks may develop and the compressive strength may be significantly reduced. As a countermeasure against this, for example, by attaching thermoplastic particles to the surface of the prepreg and arranging the particles between the layers of the molded laminate, the propagation energy of cracks due to impact is absorbed by the particles, or the particles are formed by the presence of particles. Energy is absorbed by destroying the resin layer between layers, and the area of delamination is reduced.

[0003]

In the conventional molding of aircraft structural materials by laminating prepregs, the cost becomes high as shown in the following a to c, and there is a limitation in the size which can be molded. a. A prepreg step of previously impregnating the carbon fiber material with the matrix resin is required. b. Since the primary structural material of an aircraft has a large plate thickness, a thin prepreg of about 0.2 mm is used for molding 100 to 20.
0 sheets are also stacked. Not only is the processing cost of the prepreg high, but the lamination is performed by using the tack of the prepreg and pushing out the air that is held between the prepregs with a spatula, which is very troublesome. c. Since the laminated body of these prepregs is autoclaved, a large autoclave is required, the facility cost is high, and the size of the autoclave limits the size of the molded body.

Further, the method of reducing the area of delamination has a problem that the manufacturing cost of the CFRP structural material is increased due to the following reasons d to g. d. Although it is necessary to reduce the particle size of the thermoplastic particles,
The cost of producing thermoplastic particles having a uniform particle size is high. e. A thermoplastic particle layer is required for all the prepregs arranged in each direction, and the amount of particles used increases. f. Since the thermoplastic particles are uniformly attached to the resin surface of the prepreg, the processing speed of the prepreg is slowed, and it is necessary to prepare a resin film in which the particles are dispersed in the matrix resin, which complicates the process. g. When used as the primary structural material of an aircraft, the plate thickness becomes thick.

In view of such background of the prior art, the present invention is
The present invention provides a carbon fiber cloth that is inexpensive, has high productivity, and is excellent in toughness and reliability, and that can provide CFRP, a molding method using the same, and an aircraft structural member.

[0006]

The present invention employs the following means in order to solve the above problems. That is, (1) the number of filaments of the carbon fiber yarn is more than 12,000 and less than 24,000, the tensile modulus of the carbon fiber is more than 280 GPa and less than 500 GPa, and the breaking strain energy is 53 MJ / m. A carbon fiber cloth characterized by comprising a multifilament of ^three or more carbon fibers. (2) The carbon fiber cloth according to (1), wherein the sizing adhesion amount of the carbon fiber yarn is more than 0.2% by weight and less than 0.8% by weight. (3) A unidirectional woven fabric in which the carbon fiber yarns are arranged in parallel in one direction and auxiliary yarns are arranged in the other direction to form a woven structure. (1) or (2) Carbon fiber cloth. (4) The carbon fiber cloth according to (1) or (2), which is a bidirectional woven fabric in which the carbon fiber yarns are arranged in parallel in the length direction and the width direction to form a woven structure. (5) The carbon fiber yarns are arranged in parallel to form a layered structure, which is a multiaxial stitch fabric in which these are integrated by stitch yarns. (1) or (2) Carbon fiber cloth. (6) The carbon fiber yarns are arranged in parallel to form a layer structure, and these are 0 °, + α °, 9 with respect to the length direction of the cloth.
A multiaxial fabric in which layers arranged in a direction including 0 ° and -α ° (where α is more than 0 and less than 90) are integrated by interlacing connecting yarns arranged in the 0 ° direction. The carbon fiber cloth according to (1) or (2). (7) A method for molding a carbon fiber reinforced plastic using the carbon fiber cloth according to any one of (1) to (6), which comprises the following A. B. C. 1. A molding method comprising vacuum impregnating a resin by any one of 1. A. A method in which carbon fiber cloth is laminated on a molding die, these are covered with a back film, and a resin is injected and impregnated while maintaining a vacuum inside the back film. B. A method of laminating a carbon fiber cloth on a female mold (or a male mold), clamping the mold with a male mold (or a female mold), and injecting and impregnating a resin while maintaining a vacuum in the cavity. C. A method of laminating a carbon fiber cloth on a molding die, further laminating a resin film layer serving as a matrix resin on the laminated body, covering these with a back film, and injecting and impregnating the resin while keeping the inside of the back film in vacuum. (8) A carbon fiber reinforced plastic obtained by the molding method according to (7). (9) An aircraft structural member comprising the carbon fiber reinforced plastic according to (8).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The carbon fiber used in the present invention is a multifilament yarn, and may be either PAN-based carbon fiber or pitch-based carbon fiber. Carbon fiber is used. That is,
The tensile elastic modulus (E: GPa) measured according to JIS R7601 is more than 280 GPa and less than 500 GPa, and the breaking strain energy (W: MJ / m ³ =
10 ⁶ × J / m ³ ) is a carbon fiber of 53 MJ / m ³ or more.

Here, the breaking strain energy (W)
Is a value calculated based on the following formula: W = σ ² / 2E using the tensile strength (σ: GPa) measured according to JIS R7601 and the above tensile elastic modulus (E). I mean. If carbon fibers having a tensile elastic modulus of less than 280 GPa are used, the plate thickness of the structural material must be increased in order to allow the amount of bending of the structural material, and the structural material becomes heavy. In addition, when an impact is applied, the amount of bending of the laminated plate is increased, a large peeling force is exerted between the cross-laminated layers, cracks are increased, and the compressive strength is greatly reduced by the impact, which is not preferable. Further, when it is 500 GPa or more, the breaking elongation of the carbon fiber becomes small, which is not preferable as a structural material.

In the present invention, carbon fiber having a breaking strain energy (W: MJ / m ³ ) of 53 MJ / m ³ or more is used. If the fracture strain energy is less than 53 MJ / m ³ , the impact energy absorbed by the fracture of the carbon fibers is small when the laminated plate is subjected to impact, so the energy is absorbed by the fracture of the matrix resin layer between the layers and cracks occur. Also becomes large, which is not preferable. 53MJ
When it is / m ³ or more, the impact energy absorbed by the breakage of the carbon fiber is large, the energy consumed for crack generation is small, and therefore the size of the crack is small and the reduction of the compressive strength can be small. In addition, the area damaged by impact is reduced, and the structural member has excellent reliability.

The number of filaments of the carbon fiber yarn using the carbon fiber yarn used in the present invention exceeds 12,000.
Must be less than 4,000. It is preferable to use these thick carbon fiber yarns because the carbon fiber becomes cheap and an inexpensive cloth can be obtained.

It is preferable that a sizing agent of more than 0.2 wt% to less than 0.8 wt% is attached to the carbon fiber yarn used in the present invention. The amount of sizing agent attached is 0.
When the content is 2% by weight or less, the carbon fiber on the outermost layer or the side surface of the bobbin may be handled when the bobbin wound with the carbon fiber yarn is taken out from the carton case, or when the bobbin is hung on the stitch m / c or the creel of the loom May be fluffy.
Further, when the content is 0.8% by weight or more, the carbon fibers in the carbon fiber yarn are strongly adhered to each other by the sizing agent. Therefore, when the stitch needle penetrates at high speed, the carbon fiber in the needle penetrating portion moves to the left and right of the needle. As a result, the carbon fiber cannot escape, and the carbon fiber may collide with the needle and be cut. Further, particularly in the case of a primary structural material for an aircraft, since the member thickness becomes large, the number of layers of cloth also increases, and impregnation with resin tends to become poor. 0.2
If the amount of the sizing agent is more than 0.8 wt% and less than 0.8 wt%,
Adhesion between carbon fibers with a sizing agent is moderate,
Even if the stitch needle penetrates at a high speed, the carbon fiber in the needle penetrating portion can escape by moving left and right, which is preferable. Further, since the carbon fibers are appropriately attached to each other by the sizing agent, the yarn bundle is expanded by inserting needles or stitch yarns, and a fabric having less unevenness and a smooth surface can be obtained. Becomes Further, even if the preform becomes thick, it is relatively easy to impregnate the resin.

Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an embodiment of a unidirectional woven fabric of the carbon fiber cloth of the present invention. The carbon fiber yarns 2 are arranged in the length direction of the carbon fiber cloth 1, that is, in the warp direction, the auxiliary yarns 3 thinner than the carbon fiber yarns 2 are arranged in the weft direction, and the warp yarns 2 and the weft yarns 3 are interlaced, It is a unidirectional woven fabric with a woven structure. Here, when the auxiliary yarn undergoes heat shrinkage during heating and molding, the width of the fabric becomes narrower, the density of the carbon fiber yarns orthogonal to the auxiliary yarn increases, and the state of dispersion of the carbon fibers changes. Therefore, it becomes difficult to obtain an FRP having a predetermined carbon fiber content. Therefore, the auxiliary yarn used in the present invention preferably has a low shrinkage, and
The dry heat shrinkage ratio at 00 ° C is preferably 1.0% or less,
It is more preferably 0.1% or less. As such auxiliary yarn, glass fiber yarn, polyaramid fiber yarn, etc. are preferably used. The fineness of the auxiliary yarn is preferably more than 10 tex and less than 150 tex. Especially, if it is more than 60 tex and less than 150 tex, the auxiliary yarn becomes thicker, so that the gap formed by the intersection of the auxiliary yarn and the carbon fiber yarn becomes the resin flow path during the molding, and the resin impregnation progresses. ,preferable.

FIG. 2 is a schematic plan view showing an embodiment of a bidirectional woven fabric of the carbon fiber cloth according to the present invention. The carbon fiber yarns 2 are arranged in the length direction of the carbon fiber cloth 1, that is, the warp direction, the carbon fiber yarns 4 are arranged in the weft direction, and the warp yarns 2 and the weft yarns 4 are interlaced to form a woven texture bidirectional It is a woven fabric. In the present invention, in order to make the fabric inexpensive, the number of fabrics exceeds 12,000 and 2
Since a thick carbon fiber yarn having a filament number of less than 4,000 is used, it is preferable that the yarn cross section has a flat woven structure. By crimping the thick carbon fiber yarns in a flat shape, the crimps of the warp yarn and the weft yarn can be reduced, and the high strength and high elastic modulus of the carbon fiber can be fully exhibited. Here, the flatness of the carbon fiber yarn in the woven fabric is preferably 5 or more in terms of yarn width / yarn thickness ratio. The yarn thickness referred to here is a value measured according to JIS R 7602 method for warp yarns and weft yarns unwound from a woven fabric so that the shape of the woven yarn is not broken.

[0014] in one direction textile and bidirectional fabrics described above, preferred carbon fiber basis weight is less than 800 g / m ² exceed 190 g / m ^2. If it is 190 g / m ² or less, the number of laminated layers for obtaining a predetermined CFRP plate thickness increases, which may deteriorate the workability of molding. Also, 800
If it is more than g / m ^2, the impregnating property of the resin may deteriorate.

FIG. 3 is a schematic perspective view showing an embodiment of a stitch cloth of the carbon fiber cloth according to the present invention. Figure 3
More specifically, this is an example of a multiaxial stitch fabric in which carbon fiber yarns 6 are arranged in parallel to form a layered structure, and these are integrated by stitch yarns. First, from the lower surface of the fabric 5, a large number of carbon fiber yarns 6 are arranged in parallel in an oblique direction with respect to the lengthwise direction a to form a + α ° layer 10, and then a large number of carbon fibers are provided in the width direction of the fabric. 90 ° layer 1 with yarns 7 arranged in parallel
1 and then a large number of carbon fiber yarns 8 diagonally
Are arranged in parallel to form a -α ° layer 12, and then a large number of carbon fiber yarns 9 are arranged in parallel in the length direction of the fabric to form 0.
.Degree. Layer 13 and four layers having different arrangement directions are laminated, and these four layers are sewn together by stitch yarn 14. Here, α is more than 0 and less than 90.
Further, as the stitch structure formed by the stitch thread 14 for the integral stitching, single chain stitching and 1/1 tricot knitting can be mentioned.

It should be noted that in FIG. 3, the aggregate of fibers whose cross-sectional shape is shown as an ellipse is one yarn, and it seems that the stitch yarn 14 is arranged between the yarns. The fiber aggregates, which are randomly inserted in the yarn and are shown by ellipses, are formed by the restraint of the stitch yarn. The carbon fiber structure of the multiaxial stitch fabric shown in FIG. 3 has been described as a four-layer structure of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer, but the present invention is not limited to this. For example, 0 ° layer / + 45 ° layer / 0 ° layer / −45 ° layer / 90 ° layer / −45 ° layer / 0 ° layer / + 45
° layer / 0 ° layer, such as 0 ° layer is often included,
It may include four directions of 0 °, + α °, −α °, and 90 °. It may also include any of 0 °, + α °, -α °, and 90 °.

Here, the bias angle α ° is preferably 45 ° from the viewpoint that carbon fiber stitch cloth is laminated in the length direction of the FRP molded body and shear reinforcement by carbon fibers is effectively performed. The order of the stacking angles is not particularly limited, but cracks between the CFRP layers due to impact in the thickness direction of the laminated plate due to the anisotropy of the mechanical properties of each layer are made as small as possible.
From the viewpoint of reducing the decrease in compressive strength of the CFRP plate, it is preferable that the angle of intersection of the carbon fibers of each adjacent layer is 45 °.

FIG. 4 is a schematic perspective view showing an embodiment of a multiaxial woven fabric of the carbon fiber cloth according to the present invention. In detail, FIG. 4 shows that the carbon fiber yarns are arranged in parallel to form a layered structure, and these are 0 °, + α °, 90 ° with respect to the length direction of the fabric.
This is an example of a multiaxial fabric in which layers arranged in a direction including −α ° (where α is more than 0 and less than 90) are integrated by interlacing connecting yarns arranged in the 0 ° direction. From the lower surface of the multiaxial fabric 15, first, a plurality of carbon fiber yarns 16 are arranged in parallel in the width direction of the fabric to form a 90 ° layer 21, and then a plurality of carbon fiber yarns are provided in the length direction of the fabric. 17 are arranged in parallel to form a 0 ° layer 22, and a large number of carbon fiber yarns 18 are arranged in parallel in a direction oblique to the lengthwise direction a +
The α ° layer 23 is formed, and then a large number of carbon fiber yarns 19 are diagonally arranged in parallel to form a −α ° layer 24. The four layers having different arrangement directions are straight carbon fiber yarns. A large number of connecting yarns 20 ₁ , 20 ₂ , 20 _3, ..., which are laminated in such a state and arranged in the longitudinal direction of the fabric, are inserted between the yarns of these 4 layers. This connecting yarn 20 alternately intersects with one carbon fiber yarn 19 on the upper surface and one carbon fiber yarn 16 on the lower surface, and ascending and descending in the order of upper surface → lower surface → upper surface → lower surface ... It is integrated. The structure of the carbon fiber of the multiaxial woven fabric shown in FIG. 4 is + α ° layer / 90 ° layer /
Although the four-layer structure of −α ° layer / 0 ° layer has been described, the present invention is not limited to this. For example, it may include four directions of 0 °, + α °, −α °, and 90 ° so that many 0 ° layers are included. The bias angle α ° is preferably 45 ° from the viewpoint of laminating a multiaxial woven fabric in the length direction of the FRP molded product and effectively performing shear reinforcement with carbon fibers.

Here, since the carbon fiber yarns in the layer direction of the multiaxial stitch fabric and the multiaxial fabric described in FIG. 3 or 4 are arranged straight without crimping, F
When RP is used, stress concentration does not work on the carbon fiber threads and matrix resin, and there is almost no decrease in strength or elastic modulus,
It is preferable.

The stitch yarns and connecting yarns used in the carbon fiber cloth of the present invention play a role of suppressing peeling between layers in the cloth, and for example, polyester fiber, nylon 6 fiber, nylon 66 fiber, nylon 610. Fibers, nylon 612 fibers, nylon 11 fibers, nylon 12 fibers, and copolymer fibers thereof, polyaramid fibers, vinylon fibers, low melting point fibers, glass fibers, carbon fibers and the like can be used. Among them, glass fiber, carbon fiber,
Since the polyaramid fiber has a high tensile elastic modulus, it is possible to suppress the occurrence of cracks even in a small amount, and therefore it is preferably used. In particular, since glass fibers and carbon fibers hardly absorb water, they are preferably used as reinforcing fibers for aircraft structural members. The thickness of the stitch thread or the connecting thread usually exceeds 7 depending on the kind of the fiber of the stitch thread or the connecting thread, but 15
It is preferably less than 0 tex. If it is 7 tex or less,
The effect of suppressing peeling between layers in the carbon fiber cloth becomes small. On the other hand, when the tex is 150 tex or more, the stitch yarn or the connecting yarn appears on the surface of the fabric, so that the surface of the fabric may be uneven, and the surface of the FRP may be uneven even after molding, and a smooth FRP may not be obtained. . The thickness of stitch thread and connecting thread,
More preferably, it is more than 10 tex and less than 70 tex.

Further, it is preferable that the arrangement interval of the stitch yarns in the stitch cloth is 2 to 8 mm and the pitch is about 1 to 4 mm. When the arrangement interval or pitch of the stitch yarns is small, the constraint of the carbon fiber yarns by the stitch yarns becomes strong and the drape property may be lost. Further, if the arrangement interval or pitch is increased, the drape property is improved and deep drawing can be performed, but the carbon fiber yarns may partly meander within the stitch yarn insertion interval. More preferably, the arrangement interval of the stitch yarns is 2 to 5 mm and the pitch is 2 to 3.3 mm.

The carbon fiber areal weight of each layer of the stitch fabric and the multiaxial fabric in the present invention exceeds 100 g / m ² and 500.
It is preferably less than g / m ² . There is a part where the carbon fiber does not exist in the insertion part of the stitch thread and the connecting thread,
Since resin impregnation is possible from the layer direction, resin impregnation is not hindered even with a fabric having a relatively high basis weight as compared with fabrics such as ordinary fabrics, but when it is 500 g / m ² or more, the resin impregnation rate Can be slow. Also, 100g
If it is / m ² or less, the number of fabrics required to obtain a predetermined thickness increases, and it may take time and effort to stack the fabrics. The more preferable range of the carbon fiber areal weight of each layer is 150.
Beyond the g / m ² is of less than 400 g / m ^2.

When the carbon fiber cloth of the present invention is used for molding, an interlayer toughness reinforcing material can be arranged between the carbon fiber cloths to further enhance the fracture toughness of the CFRP laminate. The shape and the like of the interlayer toughness reinforcing material are not particularly limited, and examples thereof include a sheet, a film, a non-woven fabric, a mesh, a knit, and a particle, and preferably selected from non-woven fabric, a mesh made of a thermoplastic resin, and particles made of a thermoplastic resin. More than a seed. Further, it is also possible to preliminarily bond or adhere the carbon fiber cloths to each other by the adhesion function or the adhesion function imparted to the interlayer toughness reinforcing material to form a preform shaped in the shape of a molded body.

When the interlaminar toughness reinforcing material is a non-woven fabric, mesh, knit, etc., its raw material is preferably polyester fiber, nylon 6 fiber, nylon 66 fiber, nylon 610 fiber, nylon 11 fiber, nylon 12 fiber,
And copolymer fibers thereof, polyaramid fibers, vinylon fibers, low melting point fibers, glass fibers, carbon fibers and the like. Of these, nylon fibers are excellent in adhesion with resins and are more preferably used. In particular, when the core-sheath type fiber is used, the sheath part is a low melting point thermoplastic resin, and the core part is a high melting point thermoplastic resin, when the preform is produced, the low melting point thermoplastic resin is melted to form a carbon fiber cloth. It becomes easy to bond the toughness reinforcing material and the carbon fiber cloths together.
A high melting point thermoplastic resin is preferable because it absorbs high impact energy. In addition, the interlaminar toughness reinforcing material,
It may be a mixture of high melting point thermoplastic resin fibers and low melting point thermoplastic resin fibers, interwoven or interwoven, or adhesion of high melting point thermoplastic resin fibers and low melting point thermoplastic resin powder.

The above-mentioned interlaminar toughness reinforcing material may be stitch-integrated simultaneously with the carbon fiber layer during the production of the carbon fiber cloth, or may be a low melting point thermoplastic resin melted or a low melting point thermosetting resin. It may be integrated with the carbon fiber cloth by attaching a tacky firer. Further, the low melting point thermoplastic resin can be used for melting, and the tackifier can also be used for adhesion and integration of carbon fiber cloths.

When the interlayer toughness reinforcing material is particles, the average particle diameter is preferably 1 to 150 microns. When the particle size is less than 1 micron, the particles enter between the carbon fibers forming the carbon fiber cloth, the amount of particles intervening between the layers of the carbon fiber cloth and the carbon fiber cloth decreases, and the particles evenly dispersed locally form the carbon fiber. The amount of particles interposed between the layers may vary due to intervening spaces. Also,
If the particle size exceeds 150 microns, the particle diameter becomes large, so that the number of particles to be sprayed decreases with respect to a predetermined particle spraying weight, and uniform spraying may become difficult.

The resin used as particles of the interlaminar toughness reinforcing material is preferably a thermoplastic resin such as polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyphenylene ether, polyetheretherketone, polyetherketoneketone. Examples thereof include amorphous polyamides (particularly aromatic and / or cycloaliphatic copolyamides) which have large absorption energy and low equilibrium water absorption in ASTM D 570 (preferably 3% by weight or less, Preferably 2
(Wt% or less), especially in the mechanical properties upon water absorption required for the primary structural material of the aircraft, the decrease in strength is small, which is preferable. The particles used as the interlaminar toughness reinforcing material are preferably low melting point thermoplastic resin powders or thermosetting resin powders, so-called tackifiers, and are preferably attached and integrated with the carbon fiber cloth. Further, these tacky firers can also be used for adhesion and integration of carbon fiber cloths. The tackifier made of a thermosetting resin preferably has a melting point of about 50 to 100 ° C., is made of an epoxy resin, and contains a curing agent. A tackifier containing a curing agent is preferable because the tackifier is also cured when the matrix resin is cured.

[0028] In the present invention, when using the interlayer toughness reinforcement, the amount of less than 30 g / m ² exceed 5 g / m ² is preferred. If it is less than 5 g / m ² , the effect of reinforcing the interlayer toughness between the carbon fiber cloths of the CFRP plate may be reduced. If it is 30 g / m ² or more, the heat resistance of CFRP and the strength of water absorption may decrease. More preferably, more than 7 g / m ² and 20 g / m ²
Is less than.

The method for molding a carbon fiber reinforced plastic using the carbon fiber cloth of the present invention is not particularly limited,
Preferably, A. B. C. The method of vacuum impregnating a resin by any of the above methods is used. A. It is a method in which carbon fiber cloth is laminated on a molding die, these are covered with a back film, and a resin is injected and impregnated while keeping the inside of the back film in a vacuum. Here, the carbon fiber reinforced plastic of the present invention is molded by impregnating the resin, curing the resin, and then removing from the mold. Preferably, the entire upper surface or the lower surface of the carbon fiber fabric laminate, or the entire upper surface and the lower surface, a bleeder cloth made of polyester fiber or glass fiber is laminated,
A method is used in which a mesh-shaped resin diffusion medium in which the injected resin is diffused over the entire surface is laminated thereon and the resin is injected. When this method is used, the resin spreads all over the carbon fiber cloth laminate all at once by the resin diffusion medium, and then the resin impregnation in the thickness direction of the laminate proceeds, so that the resin path becomes shorter, so the resin to the entire laminate is shortened. Is performed uniformly and the impregnation time can be shortened, which is preferable. Therefore, it is suitable for an FRP having a large area and a large plate thickness such as a structural member of an aircraft. After removing the mold, the bleeder cloth is peeled off to remove the resin diffusion medium and the cured resin accumulated in the gap between the medium. B. After laminating the carbon fiber cloth on the female type (or male type),
This is a method in which a male mold (or a female mold) is clamped and a resin is injected and impregnated while maintaining a vacuum in the cavity. Here, the carbon fiber reinforced plastic of the present invention is molded by impregnating the carbon fiber cloth laminate with the resin, curing the resin, and then demolding. Also in this case A
Similarly to the above, the resin impregnation can be accelerated by using the bleeder cloth and the resin diffusion medium, and when a groove serving as a resin flow path is provided in the mold, a large FRP can be easily molded. I can. In the molding methods of A and B, a thermosetting resin that is liquid at room temperature, such as an epoxy resin, a vinyl ester resin, a phenol resin or an unsaturated polyester resin is usually used. In order to obtain CFRP having high heat resistance, an epoxy resin is preferably used. Here, if the resin viscosity is low, the heat resistance generally deteriorates. Therefore, the mold temperature at the time of injection, the temperature of the preform and the resin are preferably 70-.
Reduce the viscosity of the injected resin to 100 ° C to reduce the resin viscosity to 2
It is preferably not more than 00 mPa · s. Then, after resin injection, post-curing is performed at about 120 ° C. to advance polymerization of the epoxy resin to at least a gel state, and then 1
It is preferable to perform after-curing at a high temperature of about 80 ° C.
By this method, CFRP having good resin impregnation, excellent heat resistance and excellent toughness can be formed. C. By laminating a carbon fiber cloth on a molding die, further laminating a resin film layer serving as a matrix resin on the laminated body, covering these with a back film, injecting a resin while keeping the inside of the back film in a vacuum, and impregnating the resin film. is there.
Here, by impregnating the resin and then removing the mold,
The carbon fiber reinforced plastic of the present invention is molded. The resin film is preferably the epoxy resin described in the above section B, for example, the epoxy resin used in the prepreg of aircraft materials, and the thickness of the film is set so that the resin amount required for resin impregnation in the laminate is set. Good. Here, since the resin film layer is provided on the entire surface of the laminated body, the impregnation into the laminated body is performed by the resin flowing in the thickness direction, the resin path is shortened, and the resin is uniformly distributed to the entire laminated body. It is also preferable because the impregnation time can be shortened.

The carbon fiber reinforced plastic of the present invention can be obtained by the above-mentioned molding method using the carbon fiber cloth of the present invention.

The use of the carbon fiber reinforced plastic of the present invention is not particularly limited, but is preferably an aircraft structural member.

FIG. 5 is a schematic perspective view of an aircraft 25 using the structural member of the present invention. Various fairings, main
In addition to secondary structural members such as landing gear doors, tail cones, engine nacelles, etc., the CFRP of the present invention is inexpensive, excellent in toughness, and excellent in mechanical properties, so that the main wing 26, tail 27, floor beam 28, fuselage 29, It can also be used for primary structural members such as wing boxes (not shown), keels (not shown).

6 and 7 show an embodiment as a structural element 30 of the present invention. Conventionally, the skin material 31, the girder material 32, and the rib material 33 were separately molded and riveted, but according to the present invention, the skin material 31, the girder material 32, and the rib material 3 are formed.
It became possible to mold 3 integrally.

[0034]

According to the present invention, the cost is low, the productivity is high,
Further, it is possible to provide a carbon fiber cloth from which CFRP having excellent toughness and reliability can be obtained, a molding method therefor, a carbon fiber reinforced plastic, and an aircraft structural member.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a unidirectional woven fabric of a carbon fiber cloth according to the present invention.

FIG. 2 is a schematic plan view showing an example of a bidirectional woven fabric of the carbon fiber cloth according to the present invention.

FIG. 3 is a schematic perspective view showing an embodiment of a stitch cloth of the carbon fiber cloth according to the present invention.

FIG. 4 is a schematic perspective view showing an example of a multiaxial woven fabric of the carbon fiber cloth according to the present invention.

FIG. 5 is a schematic perspective view of an airplane using the structural member of the present invention.

FIG. 6 is a schematic perspective view showing an embodiment as a structural element of the present invention.

FIG. 7 is a schematic perspective view showing another embodiment as a structural element of the present invention.

[Explanation of symbols]

1: Carbon fiber fabric 2: Carbon fiber yarn (warp yarn) 3: Auxiliary yarn (weft yarn) 4: Carbon fiber yarn (weft yarn) 5: Stitch fabric 6: Carbon fiber yarn of + α ° layer 7: 90 ° layer Carbon fiber yarn 8: -α ° layer carbon fiber yarn 9: 0 ° layer carbon fiber yarn 10: + α ° carbon fiber layer 11 forming a fabric 11: 90 ° carbon fiber layer 12 forming a fabric : Α-carbon fiber layer 13 forming a fabric 13: 0 ° carbon fiber layer 14 forming a fabric 14: Stitch yarn 15: Multiaxial fabric 16: 90 ° layer carbon fiber yarn 17: 0 ° layer carbon Fiber yarn 18: Carbon fiber yarn of + α ° layer 19: Carbon fiber yarn of −α ° layer 20: Connecting yarn 20 ₁ , 20 ₂ , 20 ₃ ...: Knotting yarn (connecting yarn) 21: Woven fabric Forming 90 ° carbon fiber layer 22: forming a woven fabric 0 ° carbon fiber layer 23: forming a woven fabric + α ° carbon fiber layer 2 :-.Alpha. ° carbon fiber layer 25 to form the fabric: Aircraft 26: wing 27: tail 28: floor beam 29: the fuselage 30: structural component 31: Skin material 32: spar 33: ribbing I: fabric length direction

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29K 101: 10 B29K 105: 08 105: 08 B29L 31:30 B29L 31:30 B29C 67/14 X F Term (reference) 4F205 AA39 AB11 AD16 AG03 AH31 AJ03 AM01 AM28 AR07 HA09 HA24 HA43 HA46 HB01 HB11 HC04 HC17 HF30 HG03 HK23 HM02 HM04 HM06 HT13 HT26 4L048 AA05 AB06 AC09 BA16 CA01 DA41 EB00

Claims (9)

[Claims] 1. The number of filaments of carbon fiber yarn is 12,0.
The number of carbon fibers is more than 00 and less than 24,000, the tensile modulus of carbon fibers is more than 280 GPa and less than 500 GPa, and the fracture strain energy is composed of a multifilament of carbon fibers of 53 MJ / m ³ or more. Carbon fiber cloth. 2. The carbon fiber cloth according to claim 1, wherein the amount of the sizing agent attached to the carbon fiber yarn is more than 0.2% by weight and less than 0.8% by weight. 3. The unidirectional woven fabric in which the carbon fiber yarns are arranged in parallel in one direction and auxiliary yarns are arranged in the other direction to form a woven structure. Carbon fiber cloth. 4. The carbon fiber cloth according to claim 1, which is a bidirectional woven fabric in which the carbon fiber yarns are arranged in parallel in the length direction and the width direction to form a woven structure. 5. The multi-axis stitch fabric in which the carbon fiber yarns are arranged in parallel to form a layered structure and these are integrated by stitch yarns. Carbon fiber cloth. 6. The carbon fiber yarns are arranged in parallel to form a layer structure, and these are 0 °, + α with respect to the length direction of the cloth.
A multiaxial fabric in which layers arranged in a direction including °, 90 ° and -α ° (α is more than 0 and less than 90) are integrated by interlacing connecting yarns arranged in the 0 ° direction. It exists, The carbon fiber cloth of Claim 1 or 2 characterized by the above-mentioned. 7. A method for molding a carbon fiber reinforced plastic using the carbon fiber cloth according to any one of claims 1 to 6, which comprises: B. C. 1. A molding method comprising vacuum impregnating a resin by any one of 1. A. A method in which carbon fiber cloth is laminated on a molding die, these are covered with a back film, and a resin is injected and impregnated while maintaining a vacuum inside the back film. B. After laminating the carbon fiber cloth on the female type (or male type),
A method in which a male mold (or female mold) is clamped, and resin is injected and impregnated while maintaining a vacuum inside the cavity. C. A method of laminating a carbon fiber cloth on a molding die, further laminating a resin film layer serving as a matrix resin on the laminated body, covering these with a back film, and injecting and impregnating the resin while keeping the inside of the back film in vacuum. 8. A carbon fiber reinforced plastic obtained by the molding method according to claim 7. 9. An aircraft structural member comprising the carbon fiber reinforced plastic according to claim 8.