JP3671037B2 - Reinforced fiber substrate for fiber reinforced plastics - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reinforced fiber base material used for a fiber reinforced plastic, and is devised so that the “swell” of the fiber base material can be reduced.
[0002]
[Prior art]
Fiber reinforced plastic (hereinafter referred to as “FRP”) is obtained by impregnating a fiber base material with a resin and curing the impregnated resin. Since FRP is light but high in strength, large FRP products are also manufactured.
[0003]
The large FRP products include the following.
(1) FRP blades (wind turbines, various turbine blades)
(2) FRP structure for aircraft (airframe, door, wing)
(3) Bridge [0004]
By the way, the “swell” of the fibers constituting the fiber base material has a great influence on the mechanical strength of the FRP. The greater this “swell”, the lower the mechanical strength of the FRP.
[0005]
Recently, in order to reduce the “swell”, a stitch fabric has been developed in which the fiber bundles are aligned and bundled to form a single plane instead of the woven fabric in which the fiber bundles are knitted (for example, Patent Document 1). reference).
[0006]
[Patent Document 1]
Japanese Patent Publication No. 1-25699 [0007]
[Problems to be solved by the invention]
However, also in the stitch fabric described above, the “stop yarn” or “weft” that bundles the fiber bundle is arranged so as to cross the fiber bundle. As described above, since the stop yarns are arranged so as to cross the fiber bundle, the fiber bundle is pushed by the stop yarns arranged so as to cross the fiber bundle, and the fiber bundle is bent at this portion. “Swell” occurred. In other words, the conventional “stitch fabric” does not completely eliminate the “swell”.
[0008]
In view of the above conventional description, an object of the present invention is to provide a reinforced fiber base material for fiber reinforced plastic in which the “undulation” of the fiber bundle is minimized.
[0010]
[Means for Solving the Problems]
The configuration of the present invention that solves the above problems is a sheet-like unidirectional fiber bundle group that is arranged adjacently without overlapping multiple unidirectional fiber bundles in a parallel state, and
A pair of bias mats that are arranged adjacent to each other without overlapping a plurality of unidirectional fiber bundles in a parallel state with the sheet-like unidirectional fiber bundle group interposed therebetween, and
One bias mat is arranged obliquely so that one direction fiber bundle of one bias mat and one direction fiber bundle of the sheet-like one direction fiber bundle group have a predetermined angle,
The other bias mat is disposed obliquely so that the unidirectional fiber bundle of the other bias mat and the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group have an angle opposite to the above angle.
The stitch direction is parallel to the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group, and the pair of mats are sewn together with a stop thread so as to cross the unidirectional fiber bundle of the bias mat. The directional fiber bundle group and the bias mat are bundled.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the drawings.
[0012]
<First Embodiment>
1 and 2 show a reinforcing fiber substrate 1 according to a first embodiment of the present invention. In this reinforcing fiber base 1, a sheet-like unidirectional fiber bundle group 2 is used. This sheet-like unidirectional fiber bundle group 2 is formed by arranging a large number of unidirectional fiber bundles 2a in a parallel state, adjacent to each other without overlapping, and each unidirectional fiber bundle 2a includes a plurality of unidirectional fiber bundles 2a. These fibers are aligned in parallel.
[0013]
Further, the sheet-like unidirectional fiber bundle group 2 is sandwiched between the mat 3 and the mat 4. As the pair of mats 3 and 4, a continuous fiber or short fiber of carbon fiber or glass fiber formed into a sheet and having a high porosity is adopted.
[0014]
Then, the mat 3 and the mat 4 sandwiching the sheet-like unidirectional fiber bundle group 2 are sewn together with the retaining thread 5 to bind the sheet-like unidirectional fiber bundle group 2 and the mats 3 and 4 together. At this time, the stitch direction of the retaining thread 5 is made parallel to the unidirectional fiber bundle 2a. That is, the stopper thread 5 is sewn through a position between the adjacent one-way fiber bundles 2a, and does not cross the one-way fiber bundles 2a.
[0015]
Thus, in this reinforcing fiber base 1, the stop thread 5 does not cross the unidirectional fiber bundle 2a, and other fibers do not cross the unidirectional fiber bundle 2a. Thus, since there is no fiber etc. which cross the unidirectional fiber bundle 2a, the unidirectional fiber bundle 2a has almost no “undulation”. As a result, even when a large number of reinforcing fiber base materials 1 are laminated at the time of FRP production, there is almost no “undulation” of fibers, and a high-strength FRP can be obtained.
[0016]
By the way, in the conventional stitch fabric, stop yarns are sewn so as to cross each unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group, and the unidirectional fiber bundle is the part where the stop yarn crosses. “Swelling” occurred.
[0017]
<Second Embodiment>
3 and 4 show a quasi-isotropic reinforcement type reinforcing fiber substrate 11 according to a second embodiment of the present invention. In the reinforcing fiber base 11, a sheet-like unidirectional fiber bundle group 12 is used. This sheet-like unidirectional fiber bundle group 12 is formed by arranging a large number of unidirectional fiber bundles 12a in parallel and adjacently arranged without overlapping, and each unidirectional fiber bundle 12a has a plurality of unidirectional fiber bundles 12a. These fibers are aligned in parallel.
[0018]
Further, the sheet-like unidirectional fiber bundle group 12 is sandwiched between a pair of bias sheets 13 and 14. The bias sheet 13 is a sheet in which a large number of unidirectional fiber bundles 13a are arranged adjacent to each other without being stacked in parallel, and each unidirectional fiber bundle 13a draws a large number of fibers in parallel. It is a lineup. Moreover, the sheet shape is such that the angle formed by the alignment direction of the unidirectional fiber bundles 13a of the bias sheet 13 and the alignment direction of the unidirectional fiber bundles 12a of the sheet-like unidirectional fiber bundle group 12 is θ. A bias sheet 13 is disposed obliquely with respect to the unidirectional fiber bundle group 12.
[0019]
In addition, the bias sheet 14 is a sheet in which a large number of unidirectional fiber bundles 14a are arranged in a parallel state without being stacked, and are arranged adjacent to each other, and each unidirectional fiber bundle 14a has a large number of parallel fibers. It is something that has been arranged. Moreover, the sheet is formed such that the angle formed by the alignment direction of the unidirectional fiber bundles 14a of the bias sheet 14 and the alignment direction of the unidirectional fiber bundles 12a of the sheet-like unidirectional fiber bundle group 12 is −θ. The bias sheet 14 is disposed obliquely with respect to the unidirectional fiber bundle group 12.
[0020]
Then, the bias sheet 13 and the bias sheet 14 sandwiching the sheet-like unidirectional fiber bundle group 12 are sewn together with the retaining thread 15 to form the sheet-like unidirectional fiber bundle group 12 and the bias sheets 13 and 14. Band together. At this time, the stitch direction of the retaining thread 15 is set to be parallel to the unidirectional fiber bundle 12a. That is, the stop thread 15 is sewn through a position between the adjacent unidirectional fiber bundles 12a, and does not cross the unidirectional fiber bundle 12a. More specifically, the stop thread 15 crosses the unidirectional fiber bundles 13a and 14a obliquely with respect to the bias sheets 13 and 14, but does not cross the unidirectional fiber bundle 12a in the main stress direction.
[0021]
Thus, in this reinforcing fiber base material 11, the stop thread 15 does not cross the unidirectional fiber bundle 12a in the main stress direction, and other fibers do not cross the unidirectional fiber bundle 12a in the main stress direction. Thus, since there is no fiber or the like crossing the unidirectional fiber bundle 12a in the main stress direction, the unidirectional fiber bundle 12a has almost no “swell”. As a result, even after a large number of reinforcing fiber base materials 11 are laminated at the time of FRP production, there is almost no fiber “swell” in the main stress direction, and a high-strength FRP can be obtained.
[0022]
<Modified embodiment>
In the first embodiment (FIGS. 1 and 2) and the second embodiment (FIGS. 3 and 4), the sheet-like unidirectional fiber bundle groups 2 and 12 are used. In addition, a sheet-like unidirectional fiber group (a fiber group, not a fiber bundle group) in which a large number of unidirectional fibers (one fiber thread, not a fiber bundle) are arranged in parallel and arranged adjacent to each other without overlapping. You may make it use. In this case as well, each unidirectional fiber of the sheet-like unidirectional fiber group is sewn with a stop thread so that the stop thread does not cross.
[0023]
<First embodiment>
In the first embodiment, in the reinforcing fiber base 1 shown in FIGS. 1 and 2, the unidirectional fiber bundle 2a is a carbon fiber bundle, and the mats 3 and 4 are made of carbon fiber short fibers (50 g / m ^2). ).
FRP produced by the vacuum impregnation method using this reinforcing fiber substrate 1 was excellent in mechanical properties, and a high strength FRP having a particularly high compressive strength was obtained.
[0024]
<Second embodiment>
In the second embodiment, in the reinforcing fiber base 1 shown in FIGS. 1 and 2, the unidirectional fiber bundle 2a is a carbon fiber bundle, and the mats 3 and 4 are made of glass fibers (60 g / m ² ). Made.
Since the glass fiber mat is more excellent in resin impregnation than the carbon fiber mat and is low in cost, the reinforcing fiber substrate 1 has high impregnation efficiency and low cost.
FRP produced by the vacuum impregnation method using this reinforcing fiber substrate 1 was excellent in mechanical properties, and a high strength FRP having a particularly high compressive strength was obtained. Further, since the impregnation rate of the resin is fast, the manufacturability is also excellent.
[0025]
<Third embodiment>
The third example is a reinforced fiber substrate 11 shown in FIGS. 3 and 4, in which the unidirectional fiber bundles 12a, 13a, and 14a are carbon fiber bundles, the angle θ of the bias sheet 13 on the upper surface is + 45 °, and the lower surface The bias sheet 14 has an angle −θ of −45 ° to obtain a quasi-isotropic reinforced fiber substrate.
The FRP produced by the vacuum impregnation method using this reinforcing fiber substrate 11 was excellent in mechanical properties, and a high strength pseudo isotropic reinforced FRP having a particularly high compressive strength was obtained.
[0026]
<Fourth embodiment>
In the fourth embodiment, in the reinforcing fiber base 11 shown in FIGS. 3 and 4, the unidirectional fiber bundle 12a is a carbon fiber bundle, the unidirectional fiber bundles 13a and 14a are glass fiber bundles, and the bias sheet 13 on the upper surface. Was set to + 45 °, and the angle −θ of the bias sheet 14 on the lower surface was set to −45 °, so that a quasi-isotropically reinforced fiber substrate was obtained.
Glass fiber is more excellent in resin impregnation than carbon fiber, and is low in cost. Therefore, it becomes a high-strength quasi-isotropic reinforcement type reinforcing fiber substrate 11 having high impregnation efficiency and low cost.
The FRP produced by the vacuum impregnation method using this reinforcing fiber substrate 11 was excellent in mechanical properties, and a high strength pseudo isotropic reinforced FRP having a particularly high compressive strength was obtained. Further, since the impregnation rate of the resin is fast, the manufacturability is also excellent.
[0027]
<Fifth embodiment>
In the reinforcing fiber base 11 shown in FIGS. 3 and 4, the fifth embodiment uses carbon fiber bundles as the unidirectional fiber bundles 12 a, 13 a, and 14 a, the angle θ of the bias sheet 13 on the upper surface is + 30 °, and the lower surface The bias sheet 14 has an angle −θ of −30 ° to obtain a quasi-isotropically reinforced reinforcing fiber substrate.
The FRP produced by the vacuum impregnation method using this reinforcing fiber substrate 11 was excellent in mechanical properties, and a high strength pseudo isotropic reinforced FRP having a particularly high compressive strength was obtained. Moreover, since the crossing angle of the unidirectional fiber bundles 13a and 14a was reduced, a high-strength pseudo-isotropic reinforced FRP having excellent strength in the main stress direction was obtained.
[0029]
【The invention's effect】
As described above in detail with the embodiments and examples, the sheet-like unidirectional fiber bundle group in which the unidirectional fiber bundles are arranged in a parallel state without being stacked and arranged in a sheet shape, A pair of bias mats that are arranged adjacent to each other without overlapping a plurality of unidirectional fiber bundles in a parallel state with a sheet-like unidirectional fiber bundle group in between, and one of the bias mats One bias mat is disposed obliquely so that the unidirectional fiber bundle and the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group have a predetermined angle, and the unidirectional fiber bundle of the other bias mat and the sheet The other bias mat is disposed obliquely so that the unidirectional fiber bundle of the unidirectional fiber bundle group has an angle opposite to the angle, and the unidirectional fiber of the sheet unidirectional fiber bundle group is stitched. As it becomes parallel to the bundle So as to cross the unidirectional fiber bundles of the bias mat by stitching a pair of mat by lock yarn, and the cohesive comprising constituting the sheet-like unidirectional fiber bundle group and bias mat.
With such a configuration, the stop yarn does not cross each unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group, and “swell” occurs in each unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group. Disappear. As a result, the mechanical strength of the FRP constituted by the reinforcing fiber base material is improved.
Furthermore, since the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group and the unidirectional fiber bundle of the bias mat intersect, it becomes a quasi-isotropically reinforced fiber base material.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a reinforcing fiber base according to a first embodiment of the present invention in a state in the middle of sewing.
FIG. 2 is a perspective view showing a reinforcing fiber substrate according to the first embodiment of the present invention.
FIG. 3 is a perspective view showing a reinforcing fiber base material according to a second embodiment of the present invention in a state in the middle of sewing.
FIG. 4 is a perspective view showing a reinforcing fiber substrate according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,11 Reinforcing fiber base material 2,12 Sheet-like unidirectional fiber bundle group 2a, 12a Unidirectional fiber bundle 3,4 Mat 5,15 Stopping thread 13,14 Bias sheet

Claims (1)

Sheet-like unidirectional fiber bundles that are arranged adjacent to each other without overlapping multiple unidirectional fiber bundles in a parallel state; and
A pair of bias mats that are arranged adjacent to each other without overlapping a plurality of unidirectional fiber bundles in a parallel state with the sheet-like unidirectional fiber bundle group interposed therebetween, and
One bias mat is arranged obliquely so that one direction fiber bundle of one bias mat and one direction fiber bundle of the sheet-like one direction fiber bundle group have a predetermined angle,
The other bias mat is disposed obliquely so that the unidirectional fiber bundle of the other bias mat and the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group have an angle opposite to the above angle.
The stitch direction is parallel to the unidirectional fiber bundle of the sheet-like unidirectional fiber bundle group, and the pair of mats are sewn together with a stop thread so as to cross the unidirectional fiber bundle of the bias mat. A reinforced fiber base material for fiber-reinforced plastic, characterized by binding a directional fiber bundle group and a bias mat.

Images