JP2003039429A - Fiber base for composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance smoothness of a surface by raising a strength of an outer surface of a fiber base for a composite material including an interlaminar or connecting surface's shearing strength and raising an impregnation efficiency of a matrix at the time of complexing. SOLUTION: The fiber base for the composite material is obtained by superposing single or a plurality of three-dimensional structures 3 obtained by knitting long fibers, raising the interlaminar or connecting surface's shearing strength, expediting a permeability of a matrix near and in a surface, and treating gigging 5 for enhancing the smoothness of the surface. The gigging is executed for the fiber base for the composite material obtained by superposing two-dimensional structures obtained by knitting the long fibers or superposing the two-dimensional structures and the plurality of the three-dimensional structures. The gigging is executed by needle punching. A short fiber web is inserted between fiber textures simultaneously upon the gigging at the time of the needle punching as needed. Thus, the surface is smoothed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved fiber base material for composite materials used for composites, aircraft structural members, aircraft skin panels, wing panels, window frames, heat-resistant materials, soundproofing materials and other applications. It is about.

[0002]

2. Description of the Related Art In order to obtain a predetermined shape and thickness, a fiber base material for a composite material used for the above-mentioned applications is usually a single three-dimensional base material or a plurality of superposed base materials. , At that time, a two-dimensional base material is also appropriately combined and used, and a matrix is impregnated and dried and cured,
Some are impregnated and fired to obtain finished products.

[0003]

In the case of a three-dimensional woven fabric, a conventional structure of a fiber base material for a composite material is composed of X-direction yarns, Y-direction yarns, and Z-direction yarns. In accordance therewith, there is provided, for example, a yarn in which a yarn in a direction intersecting with these at an angle of 30 °, 45 °, 60 ° or the like is additionally inserted. The yarn used for these is usually used as one yarn by aligning a required number of filaments made of continuous long fibers.

However, when the matrix is impregnated at the time of forming the composite, the impregnating property of the matrix into the internal space where the unidirectional yarns of the fiber material for the composite material intersect is low, and voids are easily formed. Therefore, the composited finished product has a problem that the interlaminar shear strength and the out-of-plane strength (peel strength) are insufficient. In addition, when a plurality of layers of three-dimensional woven fabric were used as a base material, there was no entanglement of fibers between the woven fabrics, and the joining strength of the joining surface was very weak.

Further, there is an increasing tendency to use thick fibers having a large number of single fiber diameters and aligned fibers for the purpose of cost reduction, and the convex portion due to the yarn loop at the yarn entanglement point on the surface of the fiber base material is high. As a result, the recesses formed on the surface and the adjacent joint surface become deeper by that amount, and when the matrix is impregnated at the time of compounding,
There is also a problem that the amount of matrix accumulated in the recesses becomes larger than that in other portions.

Therefore, an object of the present invention is to increase the out-of-plane strength of the fiber base material for a composite material, including the interlayer and the joint surface, and to enhance the impregnation efficiency of the matrix at the time of compositing to make the surface and joint surface smooth. It is to improve sex.

[0007]

In order to achieve the above object, the fiber base material for composite material according to claim 1 of the present invention comprises:
Three-dimensional structures woven and woven with long fibers are singly or stacked together to increase the shear strength of the interlayers and joint surfaces, and to promote the permeability of the matrix near and inside the surface and to improve the smoothness of the surface. It has been brushed.
With this configuration, when composited, the speed at which the matrix permeates into the internal space due to the capillary action of the raised portion of the yarns in each direction of the three-dimensional structure increases the impregnation time and the number of impregnations. Improve and reduce voids. After the matrix is impregnated and hardened, the binding effect between the layers or between the bonding surfaces can be increased by the anchor effect of the raised portion. Therefore, the out-of-plane strength (peel strength) including the shear strength of the interlayer and joint surface of the fiber base material for composite materials
Can be increased.

Further, in the fiber base material for a composite material according to claim 2 of the present invention, a plurality of two-dimensional structures or two-dimensional structures and three-dimensional structures woven and woven with long fibers are superposed, and the surface and the inside Further, a brushing treatment is performed to increase the shear strength of the layers and the joint surface and to promote the permeability of the matrix. With this structure, the speed at which the matrix permeates into the internal space due to the capillary phenomenon of the nap treatment part of the yarns in each direction of the three-dimensional structure or the two-dimensional structure during compounding, shortens the impregnation time and the number of impregnations. Can improve the impregnation efficiency and reduce voids. After the matrix is impregnated and hardened, the binding effect between the layers or between the bonding surfaces can be increased by the anchor effect of the raised portion. Therefore, the out-of-plane strength (peel strength) including the shear strength of the interlayer and the joint surface of the fiber base material for a composite material can be increased.

The raising process is performed by needle punching. With this configuration, the raising process can be easily performed, and the cost can be significantly reduced, and at the same time, a part of the base fiber in the plane is pushed and pushed between the gaps between the fiber bundles and the layers to form a composite. At this time, the permeability of the matrix is promoted by the action of drawing the matrix due to the capillary action of the nap raising section, the improvement of the inflow rate of the matrix through the passage hole of the needle as the entry path, and the promotion of displacement and exhaust of the internal air. Therefore, the filling rate of the matrix into the internal space can be improved by an inexpensive method, and the out-of-plane strength (peel strength) including the interlaminar shear strength of the fiber base material for composite material can be increased.

During needle punching, simultaneously with the raising process, the short fiber web layer disposed on the surface or inside is inserted and disposed in the internal space of the three-dimensional structure or the two-dimensional structure. With this configuration, some of the base fibers in the plane are pushed into the voids and layers between the fiber bundles, and at the same time short fibers are also pushed in.Therefore, the matrix pulling action by the capillary phenomenon at the time of compounding Is further improved, and the filling rate of the matrix into the internal space is increased. In addition, the anchor effect after impregnation and curing of the matrix is also improved, and the out-of-plane strength (peel strength) including the interlaminar shear strength of the fiber base material for composite material can be further increased.

The above needle punching is performed perpendicularly or at an angle to the surface of the three-dimensional structure or the two-dimensional structure. With this configuration, the raised portion of the base fiber and the pushing direction of the short fiber are appropriately set, and the interlaminar shear strength and the out-of-plane strength (peel strength) can be increased.

The convex portions of the yarn entanglement points on the surface of the three-dimensional structure or the two-dimensional structure are smoothed. With this configuration, it is possible to reduce irregularities on the surface of the fiber base material, average the amount of accumulated matrix, and eliminate the resin-rich portion.

The smoothing process of the convex portion is performed by needle punching or grinding. With this configuration, the surface of the fiber base material can be easily smoothed, and the surface of the base fiber is raised, so that the efficiency of impregnation of the matrix can be improved.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B and FIG.
3A and 3B are a schematic structure and a magnified explanatory view of a first embodiment of a fiber base material for a composite material according to the present invention, and FIGS. 3A and 3B are composite materials according to the present invention. No. 6 of textile base materials
It is a schematic structure of an embodiment, and an enlarged explanatory view thereof.

In the first embodiment shown in FIGS. 1A and 1B, the X-direction yarn 1 and the Y-direction yarn 2 are orthogonal to each other on the XY plane (a plane perpendicular to the paper surface of FIG. 1). A case in which a plurality of layers arranged in a predetermined number at intervals are laminated in the Z direction, and two layers of a three-dimensional structure 4 configured by binding the layers with Z direction yarns 3 are laminated, and in this case, the Z direction. The thread 3 is continuous by forming a chain stitch 3a on the front surface side of the three-dimensional structure 4 and forming a back stitch 3b on the back surface side. For this two-dimensional stack of three-dimensional structure 4,
A needle (not shown) having a hook-shaped or bifurcated tip is used to perform punching vertically or at an angle, and
The raised hairs 5 are formed as shown in FIG. This nap 5 has X-direction yarn 1, Y at the position where the needle has been pierced.
The whole or a part of the yarn surface of the direction yarn 2 and the Z direction yarn 3 is scraped by a hook-shaped or bifurcated tip to be fibrillated.

In the second embodiment shown in FIGS. 2A and 2B, the X-direction yarn 1 and the Y-direction yarn 2 are perpendicular to the XY plane (a plane perpendicular to the paper surface of FIG. 2). This is a case where a three-dimensional structure 4 constituted by laminating a plurality of layers arranged in a predetermined number at intervals in the Z direction and binding the layers with Z direction yarns 3 is used alone, and in this case, the Z direction yarns are used. The stripes 3 are formed by forming back stitches 3b on the front surface side and the back surface side of the three-dimensional structure 4 and continuing them. The three-dimensional structure 4 is punched vertically or at an angle with a needle (not shown) having a hook-shaped or bifurcated tip to form a nap 5 as shown in FIG. 2B. The naps 5 are the X-direction yarns 1 at the position where the needle is pierced,
It is formed by scraping all or part of the yarn surface of the Y-direction yarn 2 and the Z-direction yarn 3 by a hook-shaped or bifurcated tip and fibrillating.

The third embodiment shown in FIGS. 3A and 3B is the three-dimensional structure 4 of the first or second embodiment.
With respect to the convex portion 6 of the loop at the entanglement point of the Z-direction yarn 3 appearing on the surface of the yarn, the yarn surface is scraped and fibrillated by needle punching or grinding, and the concave portion 8 is formed by this fibrillated nap 7. Is filled in and smoothed to prevent the matrix from accumulating in the concave portion 8 and becoming a resin rich portion in the matrix impregnation step at the time of compounding.

In the first to third embodiments described above, a short fiber web layer is provided inside the three-dimensional structure 4, for example, on the intermediate layer or between the layers or on the front surface or the back surface on the needle side, and in this state. Needle punching may be performed with. By doing so, it is possible to simultaneously insert the short fibers into the internal space while subjecting the yarn fibers of the three-dimensional structure 4 to the raising process.

As described above, according to the embodiment of the present invention, the base fibers are fibrillated (raised) by needle punching, and the unidirectional yarn fibers and short fiber webs in the napped surface are sandwiched between the layers. Since the layers are pushed in and the layers are bridged, the interlaminar shear strength and the out-of-plane strength are improved. Also,
The napped fibers or short fiber webs are pushed into the voids of the unidirectional yarn fibers in the intersecting planes, the matrix is easily attracted at the time of compounding, the space is easily filled, and the impregnation efficiency is improved. Further, by using a tapered needle, a needle hole is formed, and this needle hole serves as a passageway for the matrix, thereby increasing the moving speed of the matrix and reducing voids. In addition, the impregnation time of the matrix and the number of impregnations can be reduced.

Furthermore, when thick fibers having a large number of single fibers or a large number of aligned fibers are used for cost reduction, a three-dimensional structure having large irregularities is formed on the surface, but the yarn entanglement points on the surface have little influence on the strength. By raising the loop convex part with a barbed needle or file (grinder) etc., it is possible to improve the surface property by eliminating the resin rich part when the surface is made flat and made into a composite material. .

The raising of the base fibers can be carried out by mass production by needle punching and can be provided at a low cost. Needle punching is preferably performed by needling in a direction different from the bundle direction by the binding yarn in order to increase the interlaminar shear strength. In addition, when performing needling between a plurality of stacked two-dimensional structures (fabric), it is also possible to arrange a two-dimensional structure between three-dimensional structures (fabric) and perform needling. The material of the fiber base material that becomes the preform is carbon fiber, ceramic fiber,
Examples include glass fiber and high-strength organic fiber. For example, glass-based, carbon-based, and ceramic-based inorganic fibers, as well as aramid fibers and polyester-based organic fibers can be used. The matrix can be made of polymer, carbon, ceramic, or metal such as aluminum. The fiber base material is a three-dimensional woven fabric (single or plural), a stitched (knit) preform, or a long fiber laminate (such as a laminate of two-dimensional and three-dimensional plural layers or a part of which a Z thread is inserted). A preform or the like is vertically or angled with a needle having a hook-shaped or bifurcated tip and punched at an appropriate interval density, for example, a uniform density to fibrillate the fiber surface and raise the hair.

[0022]

According to the structure of claim 1, at the time of compounding, the matrix permeates into the internal space at a higher speed due to the capillary phenomenon of the raised portion of the yarns in each direction of the three-dimensional structure,
The impregnation time can be shortened and the number of impregnations can be reduced to improve the impregnation efficiency and reduce voids. After the matrix is impregnated and hardened, the binding effect between the layers or between the bonding surfaces can be increased by the anchor effect of the raised portion. Therefore,
The out-of-plane strength (peel strength) including the shear strength of the interlayer and the joint surface of the fiber base material for a composite material can be increased.

According to the second aspect of the present invention, at the time of compounding, the matrix permeates into the internal space at a higher speed due to the capillary phenomenon of the nap treatment portion of the unidirectional yarns of the three-dimensional structure or the two-dimensional structure, so that the matrix is impregnated. The time can be shortened and the number of impregnations can be reduced, the impregnation efficiency can be improved, and the voids can be reduced. And
After the matrix is impregnated and cured, the binding effect between the layers or between the bonding surfaces can be increased by the anchor effect of the raised portion. Therefore, the out-of-plane strength (peel strength) including the shear strength of the interlayer and the joint surface of the fiber base material for a composite material can be increased.

According to the third aspect of the present invention, the raising operation can be easily carried out and mass production is possible, so that the cost can be largely reduced, and at the same time, the voids between the fiber bundles and the in-plane base material between the layers can be obtained. A part of the fiber is raised and pushed in,
The permeability of the matrix is promoted by the matrix drawing action by the capillary action of the nap raising section, the improvement of the inflow rate of the matrix through the passage hole of the needle as the entry path, and the promotion of displacement and exhaust of the internal air. Therefore, the filling rate of the matrix into the internal space is improved by an inexpensive method,
Out-of-plane strength (peel strength) including interlaminar shear strength of the fiber base material for composite material can be increased.

According to the structure of claim 4, at the same time when a part of the base fiber in the plane is fluffed and pushed between the voids between the fiber bundles and the layers, short fibers are also pushed in. Further, the action of drawing the matrix by the capillary phenomenon is further improved, and the filling rate of the matrix into the internal space is increased. Further, the anchor effect after the impregnation and curing of the matrix is also improved, and the out-of-plane strength (peel strength) including the shear strength of the interlayer and the joint surface of the fiber base material for composite material can be further increased.

According to the structure of claim 5, the raising portion of the base fiber and the pushing direction of the short fiber are appropriately set, and the shear strength and the out-of-plane strength (peel strength) of the interlayer and the joint surface can be increased. .

According to the structure of claim 6, the convex portions of the yarn entanglement points on the surface of the three-dimensional structure or the two-dimensional structure are smoothed. With this configuration, it is possible to reduce irregularities on the surface of the fiber base material, average the amount of accumulated matrix, and eliminate the resin-rich portion.

According to the structure of claim 7, the smoothing treatment of the surface of the fiber base material is facilitated, and the surface of the base fiber is raised, so that the matrix impregnation efficiency can be improved.

[Brief description of drawings]

1A and 1B are a schematic structure of a fiber base material for a composite material according to a first embodiment of the present invention and an enlarged explanatory view thereof.

2A and 2B are a schematic structure of a fiber base material for a composite material according to a first embodiment of the present invention and an enlarged explanatory view thereof.

3A and 3B are a schematic structure of a fiber base material for a composite material according to a sixth embodiment of the present invention and an enlarged explanatory view thereof.

[Explanation of symbols]

1 X direction thread 2 Y direction yarn 3 Z-direction yarn 3a chain stitch 3b backstitch 4 three-dimensional structure 5 napping 6 convex 7 napping 8 recess

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Shinya             1-11-3 Kuri, Minami-ku, Nagoya-shi, Aichi Prefecture             Shin Park No.402 (72) Inventor Takeshi Tanamura             2-7 Kaminocho, Yokaichi, Shiga Prefecture (72) Inventor Tetsuro Hirokawa             485-4 Tagamachi, Omihachiman City, Shiga Prefecture F term (reference) 3B154 AA07 AA08 AA14 AB20 BA25                       BB01 BB58 DA06 DA10 DA18                 4F072 AA04 AB28 AC02                 4F100 AD00 AD11 AG00 AK41 AK47                       BA02 BA07 BA13 BA22 DG04A                       DG12A DG13A EC09A GB90                       JK01                 4L032 AA04 AA08 AB02 AB03 AC06                       BD05 DA00 EA00

Claims (7)

[Claims] 1. A three-dimensional structure woven and woven with long fibers is singly or plurally laminated to enhance the shear strength of an interlayer or a joint surface, promotes permeability of a matrix near and inside the surface, and smoothes the surface. A fibrous base material for a composite material, which has been subjected to a nap treatment for enhancing the property. 2. A plurality of two-dimensional structures woven or woven with long fibers are superposed, or a plurality of two-dimensional structures and three-dimensional structures are superposed to increase the shear strength of an interlayer or a joint surface, and A fibrous base material for a composite material, which is internally brushed to promote the permeability of the matrix and enhance the smoothness of the surface. 3. The fiber base material for a composite material according to claim 1, wherein the raising treatment is performed by needle punching. 4. A raising process is performed by needle punching, and the short fiber web layer disposed on the surface or inside is inserted and disposed in the internal space of the three-dimensional structure or the two-dimensional structure. Item 3. The fiber base material for composite material according to Item 1 or 2. 5. The fiber base material for a composite material according to claim 3, wherein the needle punching is performed perpendicularly or at an angle to the surface of the three-dimensional structure or the two-dimensional structure. 6. The fiber base material for a composite material according to claim 1, wherein the convex portions of the yarn entanglement points on the surface of the three-dimensional structure or the two-dimensional structure are smoothed. 7. The smoothing process for the convex portion is performed by needle punching or grinding.
The fibrous base material for a composite material according to.