JP2018001475A - Preform for fiber-reinforced composite material, and fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preform for a fiber-reinforced composite material reducing ravel of the peripheral edge of a reinforced substrate in a molding process, and to provide the fiber-reinforced composite material.SOLUTION: A preform 11 for a fiber-reinforced composite material is equipped with a reinforced substrate part 17 and a shape holding part 20 disposed on the peripheral edge 19 of the reinforced substrate part 17. The reinforced substrate part 17 comprises an untwisted yarn 13 including a non-continuous reinforced fiber 15, and a covering yarn 16 covering the reinforced fiber 15 and thermally fusing in a molding process. Besides, the shape holding part 20 comprises a twist yarn 14 including the non-continuous reinforced fiber 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a preform for fiber reinforced composite material and a fiber reinforced composite material.

  In general, a fiber reinforced composite material is used as a lightweight, high-strength material. The fiber-reinforced composite material is formed by impregnating a reinforcing resin with a matrix resin to form a composite. A fiber reinforced composite material is preferable as a structural component because mechanical properties are improved as compared with a matrix resin.

  As a reinforcing substrate of a fiber reinforced composite material, there is a preform for a fiber reinforced composite material made of a woven fabric obtained by weaving warps containing reinforcing fibers and wefts containing reinforcing fibers. As a warp containing reinforcing fibers and a weft containing reinforcing fibers, for example, there is a composite spun yarn disclosed in Patent Document 1. The composite spun yarn disclosed in Patent Document 1 is formed by winding a continuous yarn made of synthetic fiber at the outer periphery of a short fiber bundle made of untwisted reinforcing fibers. In the composite spun yarn, the reinforcing fibers are oriented in the direction of the main axis of the yarn rather than the twisted yarn formed by twisting the reinforcing fibers of the short fiber bundle. Therefore, the fiber-reinforced composite material preform obtained by weaving the composite spun yarn is superior in mechanical properties in the warp direction and the weft direction as compared with the fiber-reinforced composite material preform obtained by weaving the twisted yarn.

Japanese Patent Laid-Open No. 7-118979

  By the way, in the case where a preform woven using the composite spun yarn disclosed in Patent Document 1 as warp and weft is used as a reinforced base material, composite spinning is performed in a molding process (for example, RTM (Resin Transfer Molding) molding or hot press molding). The continuous yarn of the yarn may melt by heating. When the continuous yarn of the composite spun yarn is melted by heating, the short fiber bundle is not constrained from the continuous yarn, and the fiber orientation of the short fiber bundle tends to shift. Therefore, for example, after the resin is impregnated into the preform, the resin may flow due to the press pressure by clamping, and the periphery of the preform as the reinforced base material may be released. In order to maintain uniform mechanical properties, it is necessary to cut out the peripheral edge of the reinforced base material of the fiber reinforced composite material after the molding process in order to maintain uniform mechanical properties at the location where the peripheral edge of the preform as the reinforced base material is unraveled. is there.

  The object of the present invention has been made in view of the above-described circumstances, and provides a preform for fiber-reinforced composite material and a fiber-reinforced composite material that reduce the unraveling of the periphery of the reinforced substrate during the molding process. is there.

  A preform for fiber-reinforced composite material that achieves the above object is a reinforced base material comprising a reinforcing fiber that is a non-continuous fiber, and a non-twisted yarn that covers the reinforcing fiber and that is covered and melted in the molding process. And a shape holding portion made of a twisted yarn including a reinforcing fiber which is a discontinuous fiber and is disposed on the periphery of the reinforcing base material portion.

  According to such a configuration, in the molding step, the reinforced fiber is not unraveled by twisting the twisted yarn constituting the shape holding portion disposed on the periphery of the reinforced base portion. The untwisted yarn constituting the reinforced base material portion is restrained at the periphery of the portion, so that the untwisted yarn of the reinforcing fiber is prevented from being unwound. As a result, it is possible to reduce the unraveling of the peripheral edge of the reinforced base material portion.

  The shape holding part may be composed of warps and wefts arranged on the outermost periphery of the preform for fiber reinforced composite material.

  According to this configuration, the ratio of the shape holding portion in the preform for the fiber reinforced composite material can be minimized while reducing the peripheral edge of the reinforcing base portion, so that the warp direction and the weft direction are compared with the shape holding portion. Thus, it becomes possible to maximize the proportion of the reinforced base material portion having excellent mechanical properties.

  The fiber-reinforced composite material that achieves the above object is a fiber-reinforced composite material obtained by impregnating a preform having reinforcing fibers with a matrix resin, wherein the preform is the fiber-reinforced composite material according to claim 1 or 2. It is a preform for use.

  According to such a configuration, in the molding step, the flow of the reinforcing fibers of the reinforcing base portion is suppressed by the restraint caused by the twisting of the twisted yarn disposed on the periphery of the preform for the fiber reinforced composite material. As a result, it is possible to reduce the unraveling of the peripheral edge of the reinforced base material portion.

  According to this invention, it is possible to provide a preform for fiber-reinforced composite material and a fiber-reinforced composite material that reduce the unraveling of the periphery of the reinforced base material during the molding process.

(A) is a top view of the preform for fiber reinforced composite materials. (B) is an enlarged plan view of a non-twisted yarn. (C) is an enlarged plan view of a twisted yarn. The top view of a fiber reinforced composite material. (A) is a top view which shows the modification of the preform for fiber reinforced composite materials. (B) is the sectional view on the AA line of the preform for fiber reinforced composite materials shown to (a).

  Hereinafter, a first embodiment embodying a preform for fiber reinforced composite material and a fiber reinforced composite material will be described with reference to FIGS. 1 and 2.

  First, the non-twisted yarn 13 and the twisted yarn 14 constituting the preform 11 for fiber-reinforced composite material will be described. As shown in FIG. 1 (b), the untwisted yarn 13 is formed by spinning the reinforcing fiber 15 into a non-twisted bundle, and then winding the covering yarn 16 around the untwisted reinforcing fiber 15. Yes. The reinforcing fiber 15 is a discontinuous fiber, and is composed of, for example, carbon fiber or glass fiber. The covering thread 16 is made of nylon, for example. The fiber orientation of the reinforcing fibers 15 of the non-twisted yarn 13 is oriented in the direction of the yarn main axis.

  As shown in FIG. 1C, the twisted yarn 14 is formed by twisting reinforcing fibers 15 at a predetermined twist angle. The reinforcing fiber 15 is a discontinuous fiber, and is composed of, for example, carbon fiber or glass fiber. The fiber orientation of the reinforcing fiber 15 of the twisted yarn 14 is oriented along a predetermined twist angle.

  Next, the preform 11 for fiber reinforced composite material using the untwisted yarn 13 and the twisted yarn 14 will be described. As shown to Fig.1 (a), the preform 11 for fiber reinforced composite materials is formed by plain-weaving a plurality of non-twisted yarns 13 and a plurality of twisted yarns 14.

  As shown in FIG. 1A, the reinforced base material portion 17 is formed by plain weaving warps and wefts as untwisted yarns 13. Since the reinforced substrate portion 17 is plain woven with warp and weft yarns as untwisted yarns 13, the reinforcing fibers 15 are oriented in the weft direction X and the warp direction Y. The reinforced base material portion 17 has a center 18 in which the reinforcing fibers 15 are oriented in two directions of the weft direction X and the warp direction Y, and an outer periphery of the center 18 in either the weft direction X or the warp direction Y. It consists of a peripheral edge 19 in which the reinforcing fibers 15 are oriented.

  At the peripheral edge 19 of the reinforced base material portion 17, a shape holding portion 20 is formed from warps and wefts that are the twisted yarns 14 disposed on the outermost periphery of the reinforced base material portion 17.

  As shown in FIG. 2, the fiber-reinforced composite material 10 is formed by impregnating and curing a thermosetting matrix resin 12 in a fiber-reinforced composite material preform 11 in a molding step. As an example of a manufacturing method in which the matrix resin 12 is impregnated into the fiber reinforced composite material preform 11 and cured, there is an RTM (Resin Transfer Molding) molding method. In the RTM molding method, a liquid matrix resin 12 is injected into the mold in a state where the fiber-reinforced composite material preform 11 is disposed in the resin-impregnated mold. As the thermosetting matrix resin 12, for example, an epoxy resin is used. After injecting the matrix resin 12 into the mold, the fiber reinforced composite material 10 is formed by heat curing.

Next, the operation of this embodiment will be described.
After the fiber reinforced composite material preform 11 is impregnated with the matrix resin 12 by the RTM molding method, the covering yarn 16 of the non-twisted yarn 13 is thermally melted by heating the inside of the mold. Thereafter, the matrix resin 12 flows in the mold by a press pressure by mold clamping. When the matrix resin 12 flows in the mold, the reinforcing fibers 15 that are discontinuous fibers are twisted in the twisted yarns 14 constituting the shape holding portion 20, so that the reinforcing fibers 15 can be unwound by the flow of the matrix resin 12. There is nothing. At the periphery of the reinforced base material portion 17, the restraint between the untwisted yarns 13 is weak, so that the reinforcing fibers 15 of the untwisted yarn 13 are about to be released by the flow of the matrix resin 12 in the mold. However, since the non-twisted yarn 13 at the periphery of the reinforced base material portion 17 is constrained, the reinforcing fibers 15 that are discontinuous fibers maintain the fiber orientation in the weft direction X and the warp direction Y.

According to the above embodiment, the following effects can be obtained.
(1) In the preform 11 for fiber reinforced composite material, a shape holding portion 20 composed of the twisted yarn 14 is disposed on the peripheral edge 19 of the reinforced base material portion 17 composed of the non-twisted yarn 13.
Thus, in the molding process, when the fiber reinforced composite material 10 is formed by impregnating and curing the fiber reinforced composite material preform 11 with the matrix resin 12, the shape maintained at the peripheral edge 19 of the reinforced base material portion 17 is maintained. The reinforcing fiber 15 is not unwound by twisting the twisted yarn 14 constituting the portion 20. Therefore, at the peripheral edge 19 of the reinforced base material portion 17, the untwisted yarn 13 constituting the reinforced base material portion 17 is restrained by the shape holding portion 20, and the unraveling of the reinforcing fibers 15 of the non-twisted yarn 13 is suppressed. Therefore, the unraveling of the peripheral edge 19 of the reinforced base material portion 17 due to the flow of the matrix resin 12 is reduced.

(2) The shape holding part 20 is composed of the twisted yarn 14 disposed on the outermost periphery of the peripheral edge 19 of the reinforced base part 17.
Thereby, since the ratio of the shape holding part 20 in the preform 11 for fiber reinforced composite material can be minimized, it is possible to reduce the disengagement of the peripheral edge 19 of the reinforcing base part 17 in two directions, the weft direction X and the warp direction Y. It is possible to maximize the ratio of the center 18 where the reinforcing fibers 15 are oriented.

In addition, you may change the said embodiment as follows.
○ The twisted yarn 14 constituting the shape holding portion 20 is not limited to the twisted yarn 14 disposed on the outermost periphery of the reinforced base material portion 17, but may be any twisted yarn 14 disposed on the peripheral edge of the reinforced base material portion 17. good.

The weaving method of the untwisted yarn 13 and the twisted yarn 14 is not limited to plain weave, and may be twill weave or satin weave, for example.

○ The molding method of the fiber reinforced composite material 10 is not limited to RTM molding, but may be hot press molding.

The covering yarn 16 is not limited to nylon, and may be made of a material that melts in the molding process.

The fiber-reinforced composite material 10 may be molded after the preform 11 for the fiber-reinforced composite material is shaped.

The preform 11 for fiber reinforced composite material may be composed of a three-dimensional woven fabric. For example, as shown in FIGS. 3 (a) and 3 (b), the fiber-reinforced composite material preform 11 has a fiber-reinforced composite material fabric 21 composed of a plurality of untwisted yarns 13 and a plurality of twisted yarns 14 in the thickness direction Z. It is formed by stacking. The preform 11 for fiber reinforced composite material is bonded between layers with, for example, a stitch yarn or an adhesive (not shown).

DESCRIPTION OF SYMBOLS 10 ... Fiber reinforced composite material, 11 ... Preform for fiber reinforced composite materials, 12 ... Matrix resin, 13 ... Untwisted yarn, 14 ... Twisted yarn, 15 ... Reinforced fiber, 17 ... Reinforced base material part, 19 ... Periphery, 20 ... Shape Holding part, X ... weft direction, Y ... longitudinal direction.

Claims (3)

A reinforced base material portion comprising a non-twisted yarn comprising a reinforcing fiber that is a non-continuous fiber and a covering yarn that covers the reinforcing fiber and is thermally melted in a molding process;
A preform for a fiber-reinforced composite material, comprising: a shape holding portion that is disposed on a peripheral edge of the reinforcing base portion and is formed of a twisted yarn including reinforcing fibers that are discontinuous fibers. 2. The preform for fiber reinforced composite material according to claim 1, wherein the shape holding portion is composed of warp and weft arranged on the outermost periphery of the preform for fiber reinforced composite material. A fiber-reinforced composite material obtained by impregnating a preform having reinforcing fibers with a matrix resin, wherein the preform is the preform for a fiber-reinforced composite material according to claim 1 or 2. Reinforced composite material.

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