JP2005324473A - Fiber mat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber mat for resin reinforcement which is useful for thinning the thickness of a fiber-reinforced resin plate and simplifying the constitution of the plate and can reduce a manufacturing cost consequently. <P>SOLUTION: In this fiber mat, a plurality of the fiber sheets 20, each being composed of a plurality of juxtaposed pieces of fiber 21 extending in one direction, are formed in one piece by stitching the fiber sheets 20 together with a stitching thread 30 in the lamination direction. In addition, every piece of the fiber 21 of the fiber sheet 20 is staggered nearly 60° in their orientation angle and oriented in such a way that the pieces of the fiber 21 are symmetrically laminated with the center of the lamination direction becoming a plane of symmetry. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fiber mat for resin reinforcement used as a resin reinforcing material.

  BACKGROUND ART Fiber reinforced resin (FRP) in which fibers are mixed as a reinforcing material in a resin is widely used as a material having a very high specific strength and specific elastic modulus while being lightweight. This fiber reinforced resin is obtained by impregnating a fiber mat in the form of a woven fiber sheet or chopped strand mat with a thermosetting resin or a thermoplastic resin, and passing through an aging step as necessary. The intermediate base is cured or plastically deformed to be formed into a desired shape.

  By the way, since the fiber reinforced resin uses a reinforcing material as a fiber, one property is that the anisotropy of physical properties is strong. For this reason, when the input direction is limited in the use state, the strength can be effectively obtained by the design utilizing the anisotropy. However, when the input direction is indefinite or multidirectional, it is required to have isotropic properties in which anisotropy is canceled.

  The fiber reinforced resin can be made isotropic by orienting the fibers in multiple directions. For example, in the case of the chopped strand mat, the discontinuous chopped fibers are randomly arranged, and in the case of a woven fabric, the isotropic property is obtained by means of laminating the woven fabric by changing the direction of the fibers. Provided. In particular, in a fiber mat in which fiber sheets having continuous fibers are laminated, by defining the fiber orientation angle to a certain condition, the strength is pseudo-isotropic and the elastic modulus is isotropic while exhibiting anisotropy. Can create a state called.

  The fiber mat having isotropic or pseudo-isotropic properties has the following differences depending on the fiber form. In the fiber mat using discontinuous chopped fibers such as the chopped strand mat, an intermediate base material having a high basis weight can be obtained at one time, and the physical properties are said to be relatively low. This is often used in glass fiber reinforced resin (GFRP). Moreover, in the fiber mat which laminated | stacked the fiber sheet provided with the continuous fiber, the fabric weight etc. with a low fabric weight are laminated | stacked by changing the orientation angle of a fiber, and it is said that a physical property is comparatively high. This is often used in carbon fiber reinforced resin (CFRP). The basis weight referred to here corresponds to the thickness of the fiber mat.

  Conventionally, in order to obtain FRP having high physical properties, a fiber mat in which fiber sheets such as woven fabrics of continuous fibers having a low basis weight are laminated as described above is suitable. However, in such a fiber mat, in order to make the physical properties pseudo-isotropic, it is necessary to laminate fiber sheets in multiple layers. As a result, there is a problem that the number of processes is large and productivity is inferior. Further, it is difficult to manage the fiber orientation angle when laminating the fiber sheets, and the laminating operation has a problem that it depends on a manual operation by an expert or uses expensive equipment. Furthermore, since the process of producing a woven fabric by weaving fibers and the process of laminating the woven fabric are separate, there is also a problem that the yield is deteriorated.

  In order to solve these problems, in Patent Document 1, a plurality of fiber sheets in which carbon fibers extending in one direction are juxtaposed are laminated with carbon fiber directions of 0 °, 90 °, and α °. A fiber mat (reinforcing multiaxial stitch base material) stitched in the stacking direction by stitch yarns is described.

WO 01/63033

  According to the fiber mat described in the above-mentioned patent document, since it is manufactured as a single fiber mat in advance, when the FRP is formed on the mold, the lamination process is performed simply by setting the fiber mat on the mold. Ends. Therefore, it is possible to save the labor of laminating each woven fabric one by one while changing the orientation angle of the fibers, to prevent the orientation angle from shifting, and to carry out lamination and stitching at the same time, resulting in a high yield. It has the advantage of good properties.

  However, when the fiber orientation angle of the fiber sheet includes 0 ° and 90 °, in order to have effective pseudoisotropy, an orientation angle of ± 45 °, which is an intermediate angle between those angles, is added. Necessary. For example, the fiber sheets are laminated in the lamination order such that the fiber orientation angle is 0 °, + 45 °, −45 °, 90 ° -45 °, + 45 °, 0 °. That is, it is necessary to laminate at least 7 layers of fiber sheets, which is disadvantageous when manufacturing a fiber reinforced resin having a thin plate thickness. In addition, since the layer configuration is complicated, the manufacturing equipment is also complicated, and the cost is increased.

  Therefore, the present invention provides a fiber mat for resin reinforcement that is effective in reducing the thickness of the fiber reinforced resin and has a simple configuration, and can be reduced in production cost. It is aimed.

  In the fiber mat for resin reinforcement of the present invention, a plurality of fiber sheets formed by juxtaposing a plurality of fibers extending in one direction are in a state where the orientation angles of the fibers of each fiber sheet are shifted by approximately 60 °, and The fiber orientation is characterized by being laminated in a symmetric state with the center in the laminating direction as a symmetry plane, and these fiber sheets are integrated by stitching in the laminating direction with stitch yarns.

  According to the present invention, the orientation angle of the fibers of the fiber sheet is quasi-isotropic due to the six layers configured in the stacking order of 0 °, + 60 °, −60 °, −60 °, + 60 °, 0 °. Can be obtained. Moreover, it can comprise by 5 layers by comprising 2 sheets of -60 degrees and -60 degrees of a lamination | stacking center by 1 sheet. That is, it is possible to ensure pseudoisotropy while reducing the number of layers as compared with the conventional case. For this reason, it is effective for thinning the plate | board thickness of fiber reinforced resin. In addition, since the configuration is simplified, the manufacturing cost can be reduced and the cost can be reduced.

  According to the present invention, the plurality of fiber sheets formed by juxtaposing a plurality of fibers extending in one direction are in a state in which the orientation of the fibers of each fiber sheet is shifted by approximately 60 °, and the orientation of the fibers is Since the fiber sheets are laminated in a symmetric state with the center in the laminating direction as a symmetry plane, and these fiber sheets are integrated by stitching in the laminating direction with stitch yarns, the layers of the fiber sheets are more than conventional. While it is possible to reduce the number, it is possible to ensure pseudoisotropy, and as a result, it is effective in reducing the thickness of the fiber reinforced resin and simplifies the configuration, thereby reducing the manufacturing cost. Various effects can be achieved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a structure of a belt-like resin reinforcing fiber mat 10 according to an embodiment. The fiber mat 10 is formed by laminating six fiber sheets 20, and these fiber sheets 20 are integrated by stitching together with stitch yarns 30 penetrating in the laminating direction.

  Each fiber sheet 20 is formed by juxtaposing a large number of fibers (glass fibers, carbon fibers, etc.) 21 extending in one direction. In this case, the fibers 21 are, for example, 1,000 to 100,000 fibers having a diameter of several μm. It is a tow bundled up to about this. As a specific example of the fiber 21 to be used, a relatively thick tow-shaped filament bundle having a total fineness of 70 to 6400 Tex in which a large number of filaments are converged may be mentioned. The fiber sheet 20 is configured such that such fibers 21 are juxtaposed on one side without being laminated. As a method of manufacturing the fiber sheet 20, there is a method in which the fiber 21 is drawn from the bobbin in which the fiber 21 is wound and accumulated, and the fiber 21 is reciprocated by a predetermined span and arranged in parallel.

  In the fiber mat 10, the orientation angles of the fibers 21 of the fiber sheet 20 are laminated while being shifted by 60 °. Specifically, as shown in FIG. 2, when the longitudinal direction of the fiber mat 10 is used as a reference, the fibers 21 of the two outermost fiber sheets 20A extend in a direction of 90 ° with respect to the reference direction, The fibers of the two fiber sheets 20B inside the fiber sheet 20A extend in the direction of 30 °, and the fibers 21 of the two innermost fiber sheets 20C extend in the direction of −30 °. Due to the laminated state of the fiber sheets 20A to 20C, the orientation of the fibers 21 is symmetric with the center in the lamination direction of the fiber sheets 20A to 20C, that is, between the two sheets 20C in the middle. .

  As described above, the six fiber sheets 20 are in a state where the orientations of the fibers 21 of the respective fiber sheets 20 are shifted by 60 °, and the orientations of the fibers 21 are symmetric with respect to the center in the stacking direction. By being laminated in a state, as shown in FIG. 3, the fiber mat 10 has a pseudo-isotropic structure.

  The stitch yarn 30 for integrating the fiber sheets 20 is sewn through the fiber sheets 20 by using a stitch needle, for example, by chain knitting or tricot knitting. As shown in FIG. 1, a plurality of rows of stitch yarns 30 are sewn along the longitudinal direction of the fiber mat 10. The number of the arrays and the interval between them are arbitrary, but these conditions are appropriately set in consideration of the fact that the fiber sheet 20 is firmly integrated, the shape stability is improved, and the resin is easily impregnated. Is done.

Although the kind of fiber of the stitch yarn 30 is not particularly limited, polyamide fiber, polyester fiber, polyaramid fiber, or the like is used. Further, the stitch yarn 30 preferably has stretchability, and a crimped yarn is preferably used. Moreover, it is preferable that the fabric weight of the fiber sheet 20 is a fabric weight of about 50-300 g / m < ² >, for example.

  The fiber mat 10 is set on a mold for a resin product to be obtained by a generally known process and is impregnated with a thermosetting resin to be adjusted to a product shape, or vice versa, that is, thermosetting. After being impregnated with resin, it is set on a mold and arranged into a product shape.

  According to the fiber mat 10 of the above-described embodiment, the orientation angle of the fibers 21 of the fiber sheet 20 is 90 ° and + 30 ° from the top to the bottom in the stacking direction when the longitudinal direction of the fiber mat 10 is used as a reference. , −30 °, −30 °, + 30 °, and 90 °, the fiber sheet 20 is laminated. Pseudoisotropy is obtained by the combination of the stacking order and the orientation angle of the fibers 21. Therefore, it is possible to ensure the quasi-isotropic property while reducing the number of layers as compared with the prior art, which contributes to reducing the plate thickness of the fiber reinforced resin. In addition, since the configuration is simplified by reducing the number of layers, the manufacturing cost can be reduced, and it can be obtained at a low price.

  In the fiber mat 10, the six fiber sheets 20 are made pseudo-isotropic, but the two fiber sheets 20C in the middle in which the orientation angle of the fibers 21 is set to -30 ° are equivalent to two sheets. It may be replaced with one fiber sheet having the basis weight. In that case, it can be configured with five layers, and the configuration can be further simplified.

  In addition, the above-described embodiment having a six-layer configuration in which the fiber orientation angle is shifted by 60 ° and the fiber sheet 20 is six (if the middle is one as described above) is the essential minimum When the number of the fiber sheets 20 is increased more than this, the configuration is 8 layers, 10 layers, 12 layers, and the like. In that case, if the means of making the two fiber sheets 20 in the middle one sheet having a double basis weight is taken, there are 7 layers, 9 layers, and 11 layers, respectively.

It is a perspective view which shows the structure of the fiber mat for resin reinforcement which concerns on one Embodiment of this invention. It is a schematic diagram which shows the layer structure of the fiber mat of one Embodiment. It is a top view which shows that the fiber mat of one Embodiment has pseudo-isotropic property.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Resin-reinforced fiber mat 20 (20A, 20B, 20C) ... Fiber sheet 21 ... Fiber 30 ... Stitch yarn

Claims (1)

A plurality of fiber sheets formed by juxtaposing a plurality of fibers extending in one direction are in a state where the orientation angles of the fibers of each fiber sheet are shifted by about 60 °, and the orientation of the fibers is centered in the stacking direction. A fiber mat for resin reinforcement, wherein the fiber sheets are laminated in a symmetric state as symmetry planes, and these fiber sheets are integrated by stitching in a lamination direction with stitch yarns.

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