JP2014141766A - Fiber bundle, three-dimensional fiber structure and fiber-reinforced composite material, and method for manufacturing fiber bundle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce resin accumulation and, at the same time, improve a fiber volume content in a fiber-reinforced resin when a three-dimensional fiber structure is used as a reinforcing base material for the fiber-reinforced resin.SOLUTION: In a three-dimensional fiber structure 10, an at least biaxially oriented laminated fiber layer 12 in which fiber layers 11 are laminated is bound by a binding structure 13 including binding yarns 13a arranged in a direction orthogonal to each fiber layer 11. The laminated fiber layer 12 includes at least one fiber layer 11 including fiber bundles 21 in each of which the spreading of opened fibers composing each fiber bundle 21 is restricted by nanofibers spun by an electrospinning method.

Description

  The present invention relates to a fiber bundle, a three-dimensional fiber structure, a fiber reinforced composite material, and a method for manufacturing the fiber bundle.

  Fiber reinforced composites are widely used as lightweight structural materials. There is a three-dimensional fabric (three-dimensional fiber structure) as a reinforcing base material for composite materials. A composite material using this three-dimensional woven fabric as a reinforcing base and a resin as a matrix is used as a structural member for aircraft, automobiles, ships, or general industrial equipment. The three-dimensional woven composite material is different from the fiber reinforced composite material formed by impregnating and curing resin in reinforced fabric such as woven fabric and non-woven fabric, and the direction crossing the reinforcing fiber (in-plane oriented yarn) arranged in the reference plane A three-dimensional woven fabric having binding yarns (out-of-plane direction yarns) arranged in the above is used as a reinforcing base material. Therefore, compared with a fiber reinforced composite material that does not have an out-of-plane direction yarn, there is a quality problem that cracks are likely to occur around the binding yarn (out-of-plane direction yarn) while having a high out-of-plane direction strength.

  In order to cope with this problem, a three-dimensional fiber reinforced resin composite material is proposed in which a resin is impregnated and cured in a three-dimensional fabric in which a plurality of layers of laminated in-plane direction yarns are stitched together with sewing threads made of organic fibers. Yes. (See Patent Document 1). As shown in FIG. 9, the three-dimensional fiber-reinforced resin composite material of Patent Document 1 is orthogonal to the reference plane of the in-plane direction yarn 53 composed of a plurality of warps 51 and a plurality of wefts 52 and the in-plane direction yarn 53. A plate-like three-dimensional woven fabric 56 formed of a plurality of out-of-plane direction yarns 54 and ear threads 55 that fix the out-of-plane direction yarns 54 is impregnated with resin, and the plate-like three-dimensional woven fabric 56 is impregnated with resin. It is formed by curing by heating and pressing. As the out-of-plane direction yarn 54, one having 1000 denier or less is used.

JP 2007-152672 A

  The three-dimensional fiber reinforced resin composite material of Patent Document 1 uses an organic fiber for the out-of-plane direction yarn 54, so that it has a thermal property closer to that of the matrix resin than inorganic fibers, and reduces internal strain that causes cracks. To do. Further, by using a thin thread having a denier of 1000 deniers or less, the treatment indicated by the arrows A and B in FIG. This is effective as a measure for reducing the resin pool in the gap between the tool and the in-plane direction thread 53.

  However, in these measures, as a measure for reducing the resin pool in the portion indicated by the arrow C in FIG. 9, that is, the root portion of the out-of-plane direction yarn 54, there is a contradiction that the tension of the out-of-plane direction yarn 54 cannot be increased. It is not valid. Further, if the tension of the out-of-plane direction thread 54 cannot be increased, there is a problem that the fiber volume content (about Vf 55%) of a general structural CFRP (carbon fiber reinforced resin) material cannot be realized.

  The present invention has been made in view of the above problems, and its purpose is to reduce the resin pool of the fiber reinforced resin when the three-dimensional fiber structure is used as a reinforced base material of the fiber reinforced resin. An object of the present invention is to provide a three-dimensional fiber structure and a fiber reinforced composite material capable of achieving both improvement in fiber volume content. Moreover, it is providing the fiber bundle required for the structure of the three-dimensional fiber structure, and its manufacturing method.

  The fiber bundle that solves the above problems is configured by bonding at least biaxially oriented laminated fiber layers in which fiber layers are laminated with a bonding structure having bonding yarns arranged in a direction orthogonal to each fiber layer. The fiber bundle constituting the fiber layer of the three-dimensional fiber structure, and the spread of the spread fiber is restricted by nanofibers entangled with the spread fiber constituting the fiber bundle.

  The binding yarn is arranged in a direction orthogonal to each fiber layer of the laminated fiber layer and bonds the fiber layers. When the binding yarn is tightened in the manufacturing process of the three-dimensional fiber structure, it is orthogonal to the laminated fiber layer of the binding yarn. The portions arranged in the direction to act act to widen the spacing between the fibers constituting the fiber layer. When a fiber reinforced composite material (fiber reinforced resin) is formed using a three-dimensional structure in which the distance between fibers constituting the fiber layer is widened as a reinforced base material, a resin pool is generated in the fiber reinforced resin, and from the resin pool portion Cracks are likely to occur.

  However, if the fiber layer is composed of fiber bundles in which the spread of the spread fibers constituting the fiber bundle is constrained by the nanofibers that are entangled with the spread fibers, when the binding yarn is tightened in the manufacturing process of the three-dimensional fiber structure The spread of the spread fiber constituting the fiber layer is suppressed. Therefore, when the three-dimensional fiber structure composed of this fiber bundle is used as a reinforced base material for fiber reinforced resin, it is possible to achieve both the reduction of the resin pool of the fiber reinforced resin and the improvement of the fiber volume content. it can.

  The nanofibers are preferably arranged in a state where 80% or more of those having an orientation angle of ± θ (0 <θ ≦ 15 °) with respect to a direction orthogonal to the arrangement direction of the spread fibers are present. . According to this configuration, the effect of suppressing the spread of the spread fiber is further increased.

  In the three-dimensional fiber structure that solves the above-described problems, at least biaxially oriented laminated fiber layers in which fiber layers are laminated are bonded with a bonding structure having bonding yarns arranged in a direction orthogonal to the respective fiber layers. A three-dimensional fiber structure configured, wherein the laminated fiber layer is formed from a fiber bundle in which the spread of the spread fiber is restricted by nanofibers entangled with the spread fiber constituting the fiber layer in at least one layer A fiber layer. According to this configuration, when the three-dimensional fiber structure is used as a reinforced base material for fiber reinforced resin, it is possible to achieve both reduction in the resin reservoir of the fiber reinforced resin and improvement in the fiber volume content.

  It is preferable that the laminated fiber layer has a fiber layer formed of a fiber bundle in which the spread of the spread fiber is constrained by nanofibers entangled with the spread fiber constituting the fiber layer on at least a surface layer. According to this structure, the resin pool in the surface layer of fiber reinforced resin can be reduced.

  The bonding structure is arranged along the surface of one side of the laminated fiber layer and is inserted from the one side into the laminated fiber layer at a predetermined pitch, and the other side of the laminated fiber layer A binding yarn arranged so as to be folded in a loop on the side, and a retaining yarn that prevents the binding yarn from coming off the laminated fiber layer while being inserted into the loop of the binding yarn. And a fiber layer made of a fiber bundle in which the spread of the spread fibers is constrained by nanofibers entangled with the spread fibers constituting the fiber layer on the surface layer of the laminated fiber layer on the root side of the binding yarn Is preferred.

  According to this configuration, the fiber volume content can be easily improved as compared with the configuration in which the binding yarns are wave stitched to bind the fiber layers. Moreover, the fiber layer which consists of a fiber bundle with which the spread of the spread fiber which comprises a fiber layer is restrained by the nanofiber can reduce the resin pool in the surface layer of fiber reinforced resin.

The fiber reinforced composite material which solves the said subject uses the said three-dimensional fiber structure as a reinforced base material.
According to this configuration, in the three-dimensional fiber structure as the reinforcing base material constituting the fiber-reinforced composite material, the spread of the spread fiber is constrained by the nanofiber entangled with the spread fiber constituting the fiber layer in at least one layer. And a fiber layer made of a bundle of fibers. Therefore, it is possible to achieve both a reduction in the resin reservoir of the fiber reinforced resin and an improvement in the fiber volume content.

  A method of manufacturing a fiber bundle that solves the above problem is to orient the nanofibers in the spread fibers by moving the discharge nozzle of the electrospinning device back and forth in a direction intersecting the traveling direction while moving the spread fibers. Spin in the let state. The fiber bundle produced by this method is a spread fiber in a state in which the nanofibers are oriented with a direction determined by the moving speed of the opened fiber and the moving speed of the discharge nozzle with respect to the arrangement direction of the opened fibers. Therefore, the effect of suppressing the spread of the spread fibers is greater than that in the case of random entanglement.

  According to the present invention, when a three-dimensional fiber structure is used as a reinforced base material for a three-dimensional fiber reinforced resin, a reduction in the resin reservoir of the three-dimensional fiber reinforced resin and an improvement in the fiber volume content can be achieved at the same time. Can do.

The schematic perspective view of the three-dimensional fiber structure of 1st Embodiment. The schematic diagram of a one-way fabric. (A) is a schematic perspective view of the fiber bundle of a surface layer, (b) is a schematic cross section which shows the state where an opening fiber and a nanofiber become intertwined. The schematic diagram which shows the manufacturing method of a fiber bundle. The schematic cross section of fiber reinforced resin. (A) is a schematic perspective view of the fiber bundle of 2nd Embodiment, (b) is a schematic cross section. The schematic cross section of the three-dimensional fiber structure of another embodiment. The schematic cross section of the three-dimensional fiber structure of another embodiment. The schematic cross section of a prior art.

(First embodiment)
Hereinafter, 1st Embodiment of a fiber bundle, a three-dimensional fiber structure, and a fiber reinforced composite material is described according to FIGS.

  As shown in FIG. 1, the three-dimensional fiber structure 10 includes a binding fiber 13 a in which laminated fiber layers 12 having at least biaxial orientation in which fiber layers 11 are laminated are arranged in a direction orthogonal to the fiber layers 11. It is configured to be coupled by a coupling structure 13 having the same. Specifically, the coupling structure 13 includes a coupling yarn 13a and a retaining yarn 13b. The binding yarns 13a are arranged along the surface of one side of the laminated fiber layer 12 (the lower side in FIG. 1) and are inserted into the laminated fiber layer 12 from the one side with a predetermined pitch. The fiber layer 12 is arranged so as to be folded back in a loop shape on the other surface side. The retaining thread 13b crosses the arrangement surface Pz of the binding thread 13a so as to prevent the binding thread 13a from slipping out of the laminated fiber layer 12 in a state of being inserted into the loop L of the binding thread 13a (this embodiment) In the orthogonal direction).

  In this embodiment, the laminated fiber layer 12 includes a fiber layer 11a composed of continuous fibers having an orientation angle of 0 degrees, a fiber layer 11b composed of continuous fibers having an orientation angle of 90 degrees, and a fiber layer composed of continuous fibers having an orientation angle of 45 degrees. 11c and a fiber layer 11d made of continuous fibers with an orientation angle of −45 degrees are laminated in a predetermined number so as to be pseudo-isotropic. A fiber layer 11c made of continuous fibers with an orientation angle of 45 degrees or a fiber layer 11d made of continuous fibers with an orientation angle of -45 degrees is arranged on both surfaces of the laminated fiber layer 12 in the thickness direction. The continuous fibers of the laminated fiber layer 12 become in-plane arrangement yarns arranged in a plane orthogonal to the thickness direction of the three-dimensional fiber structure 10 (vertical direction in FIG. 1). The binding yarn 13a constitutes an out-of-plane direction yarn arranged in a direction intersecting with the in-plane arrangement yarn arranged in the reference plane.

  As shown in FIG. 2, the fiber layer 11 includes a fiber bundle layer 15 composed of fiber bundles 14 of continuous fibers 14 a arranged in one direction and functioning as reinforcing fibers, and an auxiliary arranged in a direction perpendicular to the fiber bundle 14. It is comprised with the thread | yarn 16. The auxiliary yarn 16 does not have a function as a reinforcing fiber, and plays a role of binding the fiber bundle 14 and handling it as a woven fabric. That is, the fiber layer 11 is composed of a unidirectional fabric.

  As the continuous fiber 14a, the binding yarn 13a, and the retaining yarn 13b, for example, carbon fiber is used. Carbon fiber has a number of filaments of about several hundred to several tens of thousands, and the number of fiber bundles suitable for the required performance is selected.

  The laminated fiber layer 12 has a fiber layer composed of a fiber bundle 21 in which the spread of the spread fibers constituting the fiber bundle is constrained by nanofibers 20 (illustrated in FIG. 3) spun by an electrospinning method. . In this embodiment, the surface layer has a fiber layer composed of fiber bundles 21. In this embodiment, among the fiber layers 11, the fiber layer 11 constituting the surface layer is composed of the fiber bundle 21 and the auxiliary yarn 16.

  As shown in FIGS. 3A and 3B, when the fiber bundle 21 is schematically shown, the fiber bundle 21 is arranged in one direction with a plurality of continuous fibers 21a opened, The spread of the spread fiber is constrained by the nanofiber 20 in a state of being randomly entangled with the continuous fiber 21a. For this reason, the fiber bundle 21 is used to form one surface layer of the laminated fiber layer 12 constituting the three-dimensional fiber structure 10, and the binding yarn 13 a constituting the joining structure 13 of the laminated fiber layer 12 is used as the fiber bundle 21. If the structure is inserted into the laminated fiber layer 12 from the fiber layer side, the force acting to spread the spread fiber from the binding yarn 13a is efficiently suppressed. Moreover, since the nanofiber 20 is integrated with the spread fiber of the fiber bundle 21, that is, the continuous fiber 21a, and restrains the spread of the spread fiber, it is not necessary to add a fiber layer for suppressing the spread. As a result, there is no adverse effect on product properties such as weight increase.

  The resin used for the nanofiber 20 can be molded as a resin having a nano-order diameter and can be applied as long as it is a thermoplastic synthetic resin. Examples thereof include polyester and nylon.

Next, a method for producing a fiber bundle 21 in which nanofibers 20 are entangled with an open fiber by an electrospinning method will be described.
A known electrospinning apparatus is used for the electrospinning method. As shown in FIG. 4, the electrospinning apparatus 30 includes a high-voltage power supply 31, a discharge nozzle 32, and a target electrode 33 disposed so as to face the discharge nozzle 32. The high voltage power supply 31 can output about 10 to 20 kV. The discharge nozzle 32 is connected by a pipe 34 to a resin solution supply unit (not shown). The resin solution supply unit is configured to supply a tank for storing a molten resin and a resin melted by applying pressure in the tank to the discharge nozzle 32. The plus terminal of the high voltage power supply 31 is electrically connected to the discharge nozzle 32, and the minus terminal of the high voltage power supply 31 and the target electrode 33 are grounded.

  The target electrode 33 has a width equal to or larger than the width of the spread fiber 35 that moves in one direction between the discharge nozzle 32 and the target electrode 33. The discharge nozzle 32 is configured to be reciprocally movable in a direction orthogonal to the moving direction of the spread fiber 35 by a driving device (not shown).

  When the fiber bundle 21 is manufactured, the raw fiber bundle is opened by an unshown opening device to form the opened fiber 35, and the opened fiber 35 is unidirectional between the discharge nozzle 32 and the target electrode 33. So as to move to the winding device via a take-up device (not shown). The molten resin discharged from the discharge nozzle 32 travels toward the target electrode 33 with a positive charge, and the spread fibers 35 pass in one direction between the discharge nozzle 32 and the target electrode 33 (in FIG. 4, perpendicular to the paper surface). During the movement in the direction), the nanofibers 20 enter between the continuous fibers 21a constituting the opened fibers 35 and are entangled with the opened fibers 35.

  The spread fiber 35 is moved at a constant speed, and the discharge nozzle 32 reciprocates within the width of the spread fiber 35 and is moved in a state where the speed is randomly changed during the movement. As a result, as shown in FIGS. 3 (a) and 3 (b), a plurality of continuous fibers 21a are arranged in one direction in an opened state, and are randomly engaged with the continuous fibers 21a as the opened fibers. The fiber bundle 21 in which the spread of the spread fiber is restricted is manufactured by the nanofiber 20.

  The three-dimensional fiber structure 10 is used as a reinforcing base material for a fiber-reinforced composite material. The fiber reinforced composite material is configured by impregnating and curing a three-dimensional fiber structure 10 with, for example, a thermosetting resin such as an epoxy resin.

  As shown in FIG. 5, the fiber reinforced resin 40 as the fiber reinforced composite material is three-dimensional in a state where the binding yarn 13a constituting the three-dimensional fiber structure 10 is engaged with the retaining yarn 13b at the loop-shaped folded portion. The fiber structure 10 is arranged in a folded shape in the thickness direction, and is arranged along the surface of the three-dimensional fiber structure 10 on the side opposite to the loop-shaped folded part, that is, on the root side. On the base side of the binding yarn 13a, when forming the three-dimensional fiber structure 10, the binding yarn 13a arranged in a folded shape is pulled back at each insertion position in order to increase the fiber volume content Vf of the laminated fiber layer 12. At this time, a force in the direction of increasing the distance between the continuous fibers 21a engaged with the binding yarn 13a on the base side of the binding yarn 13a acts greatly. However, since the spread of the spread fiber is constrained by the nanofiber 20 spun by the electrospinning method, the spread of the fiber bundle 21 is suppressed. As a result, the binding yarn 13a inserted in the folded shape into the laminated fiber layer 12 is impregnated and cured with the resin in a state in which the opening is prevented. Therefore, the fiber reinforced resin 40 has a small resin reservoir 41 at the base portion of the binding yarn 13a. 5 schematically illustrates the binding yarn 13a inserted between adjacent fiber bundles 21, the probability that the binding yarn 13a is inserted between the opened fibers of the fiber bundle 21. Is expensive.

According to this embodiment, the following effects can be obtained.
(1) The fiber bundle 21 is bonded by a bonding structure 13 in which laminated fiber layers 12 having at least biaxial orientation in which the fiber layers 11 are laminated have bonding yarns 13 a arranged in a direction orthogonal to the fiber layers 11. The fiber layer 11 of the three-dimensional fiber structure 10 configured as described above is configured, and the spread of the spread fibers 35 configuring the fiber bundle 21 is constrained by the nanofibers 20 spun by the electrospinning method. Therefore, when the three-dimensional fiber structure 10 composed of the fiber bundles 21 is used as a reinforcing base material of the fiber reinforced resin 40 (fiber reinforced composite material), the reduction of the resin reservoir 41 in the surface layer of the fiber reinforced resin 40 is reduced. Further, the improvement of the fiber volume content Vf can be achieved.

  (2) The three-dimensional fiber structure 10 includes a bonded structure 13 in which a laminated fiber layer 12 having at least biaxial orientation in which fiber layers 11 are laminated has a binding yarn 13 a arranged in a direction orthogonal to the fiber layers 11. It is combined with. And the laminated fiber layer 12 has the fiber layer 11 which consists of the fiber bundle 21 in which the spread of the spread fiber 35 which comprises the fiber bundle 21 is restrained by the nanofiber 20 spun by the electrospinning method at least in one layer. Therefore, when the three-dimensional fiber structure 10 is used as a reinforced base material for the fiber reinforced resin 40, it is possible to achieve both reduction of the resin reservoir 41 in the surface layer of the fiber reinforced resin 40 and improvement of the fiber volume content Vf. it can.

  (3) The laminated fiber layer 12 includes at least a fiber layer 11 including a fiber bundle 21 in which the spread of the spread fibers 35 constituting the fiber layer 11 is constrained by nanofibers 20 spun by an electrospinning method. Have. Therefore, the resin reservoir 41 in the surface layer of the fiber reinforced resin 40 can be reduced.

  (4) Since the nanofiber 20 is integrated with the spread fiber of the fiber bundle 21, that is, the continuous fiber 21 a and restrains the spread of the spread fiber, there is no need to add a spread suppressing fiber layer to the laminated fiber layer 12. . As a result, there is no adverse effect on product properties such as weight increase.

  (5) The bonding structure 13 is arranged along the surface of one side of the laminated fiber layer 12 and is inserted from the one side into the laminated fiber layer 12 at a predetermined pitch. A binding yarn 13a arranged so as to be folded in a loop shape on the other surface side, and a retaining yarn 13b that prevents the binding yarn 13a from coming off the laminated fiber layer 12 while being inserted into the loop L of the binding yarn 13a. It consists of and. And the spread of the spread fiber 35 which comprises the fiber bundle 21 is restrained by the nanofiber 20 spun by the electrospinning method on the surface layer of the laminated fiber layer 12 on the root side of the binding yarn 13a. It has a fiber layer 11. Therefore, the fiber volume content Vf can be easily improved as compared with the configuration in which the binding yarns 13a are wave-sewn to join the fiber layers 11 together. Further, the resin layer 41 in the surface layer of the fiber reinforced resin 40 can be reduced by the fiber layer 11 including the fiber bundle 21 in which the spread of the spread fiber 35 constituting the fiber layer 11 is constrained by the nanofiber 20.

  (6) The three-dimensional fiber structure 10 as a reinforcing base material of the fiber reinforced resin 40 (fiber reinforced composite material) is a nano-fiber in which the spread of the spread fibers constituting the fiber bundle 21 is spun by at least one layer by an electrospinning method. It has the fiber layer 11 which consists of the fiber bundle 21 restrained by the fiber 20. Therefore, it is possible to achieve both reduction of the resin reservoir 41 in the surface layer of the fiber reinforced resin 40 and improvement of the fiber volume content Vf.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In this embodiment, the method of manufacturing the fiber bundle 21 in which the spread of the spread fibers 35 constituting the fiber layer 11 of the laminated fiber layer 12 is constrained by the nanofibers 20 spun by the electrospinning method is the same as that of the first embodiment. Is different. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the method of manufacturing the fiber bundle 21, the nanofiber 20 is oriented in the spread fiber 35 by moving the discharge nozzle 32 of the electrospinning device 30 back and forth in a direction crossing the traveling direction while moving the spread fiber 35. Spin in the let state. More specifically, the electric field is set in a state where the moving speed of the spread fiber 35 and the moving speed of the discharge nozzle 32 are set so that the orientation angle of the nanofiber 20 with respect to the arrangement direction of the opened fibers 35 is set. Electrospinning is performed by the spinning device 30. As a result, as shown in FIG. 6A, the nanofibers 20 are arranged in a state where the orientation angle is ± θ with respect to the direction orthogonal to the arrangement direction of the spread fibers 35. Further, as shown in FIG. 6B, the nanofibers 20 are also arranged in a state where they penetrate into the thickness direction of the spread fiber 35 and are entangled with the continuous fibers 21a.

According to this embodiment, in addition to the effects described in (1) to (6) of the first embodiment, the following effects can be obtained.
(7) The fiber bundle 21 is manufactured by moving the opening fiber 35 in a direction crossing the traveling direction while reciprocating the discharge nozzle 32 of the electrospinning device 30 to move the opening fiber 35 into the opening fiber 35. Spin with 20 oriented. Therefore, the fiber bundle 21 manufactured by this method is oriented with the directionality determined by the moving speed of the opened fibers 35 and the moving speed of the discharge nozzles 32 with respect to the arrangement direction of the opened fibers 35. Since the crossing and entanglement with the spread fiber 35 is performed in this state, the effect of suppressing the spread of the spread fiber 35 is greater than in the case of entanglement at random.

  (8) The nanofibers 20 are arranged in a state where 80% or more of the orientation angles of ± θ (0 <θ ≦ 15 °) are present with respect to the direction orthogonal to the arrangement direction of the spread fibers 35. . Therefore, the effect of suppressing the spread of the spread fiber 35 is greater than when the orientation angle θ exceeds ± 15 °.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The laminated fiber layer 12 constituting the three-dimensional fiber structure 10 is a fiber bundle 21 in which the spread of spread fibers is constrained by nanofibers 20 spun by an electrospinning method on at least one fiber layer 11. What is necessary is just to have the comprised fiber layer 11. FIG. For example, as shown in FIG. 7, the fiber layer 11 composed of fiber bundles 21 is formed on the side of the laminated fiber layer 12 where the loop L of the binding yarn 13a exists, that is, the insertion side (root side) of the binding yarn 13a. ) May be disposed on the surface layer on the opposite side. In the fiber reinforced resin 40 using the three-dimensional fiber structure 10 as a reinforced base material, the resin pool 41 at the intersection of the binding yarn 13a and the retaining yarn 13b is reduced. Further, the fiber layer 11 composed of the fiber bundles 21 may be arranged as an intermediate layer instead of the surface layer of the laminated fiber layer 12. Even in this case, although it is not as large as the surface layer side, the resin reservoir which exists also in the intermediate layer can be reduced. However, when only one fiber layer 11 composed of the fiber bundles 21 is disposed, it is preferably disposed on the surface layer on the root side of the binding yarn 13a.

  (Circle) the fiber layer 11 comprised by the fiber bundle 21 is good also as not only one layer but a multiple layer. For example, it is arranged on both surface layers of the laminated fiber layer 12, it is also arranged on the intermediate layer in addition to both surface layers, it is arranged on the surface layer and the intermediate layer on the root side of the binding yarn 13a, or plural in arbitrary positions Layers may be arranged. However, when a plurality of fiber layers 11 composed of fiber bundles 21 are arranged, at least one layer is preferably arranged on the surface layer on the root side of the binding yarn 13a.

  The laminated fiber layer 12 only needs to be at least biaxially oriented by laminating the fiber layer 11, and each fiber layer 11 does not have to be composed of a unidirectional woven fabric, and both the warp and the weft have the function of reinforcing fibers. You may comprise the textile fabric woven with the flat fiber bundle which fulfills. Examples of the woven fabric include a plain woven fabric and a twill woven fabric. Moreover, a plain fabric and a twill fabric may be mixed. When the fiber layer 11 is composed of a woven fabric, one woven fabric forms two layers of fiber layers 11 having different orientation directions. When the woven fabrics are laminated, the laminated fiber layers 12 have a configuration in which reinforcing fibers are arranged in a four-axis orientation if the warp and weft arrangement directions of the woven fabrics are laminated 45 ° apart from each other.

The laminated fiber layer 12 may have a laminated configuration in which a woven fabric made of flat fiber bundles and a unidirectional fabric are mixed.
(Circle) you may comprise the fiber layer 11 comprised by the fiber bundle 21 with a textile fabric.

  The coupling structure 13 that couples the fiber layers 11 of the laminated fiber layer 12 is not limited to the configuration that includes the coupling thread 13a and the retaining thread 13b. For example, as illustrated in FIG. You may make it the structure which couple | bonds each fiber layer of the laminated fiber layer 12. FIG.

  ○ The lamination order of the fiber layers 11a to 11d that constitute the laminated fiber layer 12 in a pseudo-isotropic and in-plane four-axis orientation is such that the outer layer is the fiber layer 11c (+45 degree layer) or the fiber layer 11d (-45 degree layer). The order is not limited.

  When there are a large number of fiber layers 11 to be laminated, there may be a portion where the fiber layers 11 having the same fiber arrangement direction are adjacent to each other without being laminated so that the fiber arrangement directions of the adjacent fiber layers 11 are different. .

  ○ The resin used for the nanofiber 20 reinforces the physical properties of the matrix resin of the fiber reinforced resin. For example, the resin used for the nanofiber 20 is the same resin as the matrix resin of the fiber reinforced resin or a resin having good compatibility. Is preferable.

  ○ After spinning the nanofibers 20 so as to be entangled with the spread fibers constituting the fiber bundle 21, the nanofibers 20 may be fixed (welded) to the fiber bundle by applying heat. In this case, the effect of suppressing the spread of the spread fiber is improved.

  ○ The continuous fiber constituting the laminated fiber layer 12 is not limited to carbon fiber, but aramid fiber, poly-p-phenylenebenzobisoxazole fiber, ultrahigh molecular weight polyethylene fiber, etc., corresponding to the physical properties required for fiber reinforced composite materials High-strength organic fibers or inorganic fibers such as glass fibers and ceramic fibers may be used.

  O As a method of entanglement of the spread fiber constituting the fiber bundle 21 and the nanofiber 20, another entanglement method such as needling may be used instead of the electrospinning method.

  θ ... orientation angle, L ... loop, 10 ... three-dimensional fiber structure, 11, 11a, 11b, 11c, 11d ... fiber layer, 12 ... laminated fiber layer, 13 ... bonding structure, 13a ... bonding yarn, 13b ... retaining Threads 14, 21 ... fiber bundles, 20 ... nanofibers, 30 ... electrospinning apparatus, 32 ... discharge nozzle, 35 ... open fiber, 40 ... fiber reinforced resin as a fiber reinforced composite material.

Claims (7)

  The fiber layer of the three-dimensional fiber structure, wherein the fiber layers are laminated and the laminated fiber layers that are at least biaxially oriented are joined by a joining structure having binding yarns arranged in a direction orthogonal to the fiber layers. The fiber bundle is characterized in that the spread of the spread fiber is restricted by nanofibers entangled with the spread fiber constituting the fiber bundle.   The nanofibers are arranged in a state where 80% or more of the nanofibers have an orientation angle of ± θ (0 <θ ≦ 15 °) with respect to a direction orthogonal to the arrangement direction of the spread fibers. The fiber bundle as described in 2. A laminated fiber layer in which at least biaxial orientation in which fiber layers are laminated is a three-dimensional fiber structure configured by being bonded with a bonding structure having bonding yarns arranged in a direction orthogonal to each fiber layer,
The three-dimensional fiber structure according to claim 1, wherein the laminated fiber layer has at least one fiber layer made of the fiber bundle according to claim 1.   The said laminated fiber layer is a three-dimensional fiber structure of Claim 3 which has a fiber layer which consists of a fiber bundle of Claim 1 or Claim 2 in the surface layer at least.   The bonding structure is arranged along the surface of one side of the laminated fiber layer and is inserted from the one side into the laminated fiber layer at a predetermined pitch, and the other side of the laminated fiber layer A binding yarn arranged so as to be folded in a loop on the side, and a retaining yarn that prevents the binding yarn from coming off the laminated fiber layer while being inserted into the loop of the binding yarn. The three-dimensional fiber structure according to claim 3 or 4, wherein a fiber layer comprising the fiber bundle according to claim 1 or 2 is provided on a surface layer of the laminated fiber layer on a root side of the binding yarn.   The fiber reinforced composite material which uses the three-dimensional fiber structure of any one of Claims 3-5 as a reinforced base material.   A fiber characterized in that the fiber is spun while the nanofibers are oriented in the opened fiber by reciprocating the discharge nozzle of the electrospinning device in a direction crossing the traveling direction while moving the opened fiber. A method of manufacturing a bundle.