JP2010047875A - Fibrous structural material, method for producing the same and method for producing fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the productivity of a fibrous structural material for reinforcing a resin and a fiber-reinforced composite material. <P>SOLUTION: The fibrous structural material 11 is constituted by a plurality of reinforcing fiber layers 12, 13, 14, 15 consisting of fiber bundles 121, 131, 141, 151 for reinforcing the resin, a plurality of resin fiber layers 16, 17, 18, 19, 20 consisting of fiber bundles 161, 171, 181, 191, 201 made from a thermoplastic resin, fall off-stopping yarns 21 made from a thermoplastic resin and restricting yarns 22 made from a thermoplastic resin. On heating and compressing the fibrous structural material 11, the resin fiber layers 16-20, fall off-stopping yarns 21 and restricting yarns 22 are melted, and on solidifying the molten thermoplastic resin, the fiber-reinforced composite material 11A is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fiber structure for resin reinforcement, a method for producing a fiber structure, and a method for producing a fiber-reinforced composite material in which a resin is reinforced with a fiber structure.

  In a fiber reinforced composite material in which a resin is reinforced using a fiber structure made of carbon fiber, glass fiber, aramid fiber, etc. as a reinforcing material, a thermosetting resin is generally used as a matrix resin, but time is required for molding. There is a problem that productivity is low because it takes.

Patent Document 1 discloses a multiaxial woven fabric in which a multiaxial woven fabric substrate and a thermoplastic resin film are integrated by stitching together with stitch yarns (constraint yarns). By heating the multiaxial woven fabric, the thermoplastic resin film is melted, and the molten thermoplastic resin penetrates into the multiaxial woven fabric substrate to form a composite sheet. A fiber reinforced composite material can be obtained by laminating a plurality of such composite sheets or by heating and pressing one in a mold.
JP 2006-291369 A

  However, when stitching the multiaxial woven fabric base material and the thermoplastic resin film with stitch yarn, if the thickness of the thermoplastic resin film is large, the multiaxial woven fabric base material and the thermoplastic resin film are inserted to pass the stitch yarn. It becomes difficult to pass the needle through the thermoplastic resin film. If the thickness of the thermoplastic resin film is reduced, the insertion needle can be easily passed through the thermoplastic resin film. In this case, however, the number of thermoplastic resin films increases. This increase in the number of sheets increases the time for the step of laminating the multiaxial woven fabric base material and the thermoplastic resin film, and the productivity becomes worse.

  An object of this invention is to improve the productivity of the fiber structure for resin reinforcement, and a fiber reinforced composite material.

  The first to fifth aspects of the present invention are directed to a fiber structure for resin reinforcement used for producing a fiber-reinforced composite material in which a resin is reinforced with fibers. A reinforcing fiber layer, a resin fiber layer made of continuous fibers made of thermoplastic resin, and a constraining yarn for bonding the laminated reinforcing fiber layer and the resin fiber layer.

  Resin reinforcement is to impregnate a molten resin between reinforcing fibers to integrate the resin and fibers as a fiber-reinforced composite material. The insertion needle for the binding yarn is easy to pass through the resin fiber layer, and it is easy to form a resin fiber layer by arranging continuous fibers made of thermoplastic resin. Therefore, the productivity of the fiber structure is improved.

In a preferred example, the outermost layer of the fiber structure is the resin fiber layer.
The surface of the resin fiber layer can be smoothed when the fiber reinforced composite material is formed by melting the resin fiber layer.

In a preferred example, the constraining yarn is made of a thermoplastic resin.
When the resin fiber layer is melted to form a fiber reinforced composite material, the binding yarn is also melted, so that the surface smoothness of the resin fiber layer is increased.

In a preferred example, the resin of the constraining yarn has a melting point higher than that of the resin fiber layer.
Even after the resin fiber layer is melted, the binding yarn does not melt for a while. This contributes to suppression of misalignment of the continuous fibers for resin reinforcement.

In a preferred example, a retaining thread that engages with the restraining thread is provided.
When the fiber arrangement direction of the outermost fiber layer of the fiber structure is the same as the stitching direction of the binding yarn, if the retaining thread is used outside the fiber layer, the restraining yarn is prevented from coming off.

  The inventions according to claims 6 to 8 are directed to a method for producing a fiber structure for resin reinforcement used for producing a fiber reinforced composite material in which a resin is reinforced with fibers. A lamination step of laminating a fiber layer and a resin fiber layer; and an insertion step of inserting a constraining yarn so as to bond the laminated reinforcing fiber layer and the resin fiber layer. The resin fiber layer is formed by arranging continuous fibers made of thermoplastic resin.

The method of arranging continuous fibers to form a reinforcing fiber layer and a resin fiber layer is advantageous for improving the productivity of the fiber structure.
In a preferred example, the constraining yarn is made of a thermoplastic resin.

The smoothness of the surface of the resin fiber layer is increased.
In a preferred example, the resin of the constraining yarn has a melting point higher than that of the resin fiber layer.
When the melting point of the resin of the constraining yarn is higher than the melting point of the resin fiber layer, the displacement of the continuous fibers for resin reinforcement is suppressed.

  The inventions of claim 9 and claim 10 are directed to a method for producing a fiber reinforced composite material in which a resin is reinforced by a fiber structure. In the invention of claim 9, a lamination step of laminating a reinforcing fiber layer and a resin fiber layer. And an insertion step of inserting a constraining yarn so as to bond the laminated reinforcing fiber layer and the resin fiber layer, and an arrangement step of arranging the fiber structure manufactured through the insertion step in a mold, A heating / pressurizing step for performing pressurization and heating in the mold, and a cooling step for cooling the heated / pressurized fiber structure.

Such a manufacturing method increases the productivity of the fiber-reinforced composite material.
In a preferred example, the constraining yarn is made of a thermoplastic resin, the melting point of the resin of the constraining yarn is higher than the melting point of the resin fiber layer, and the heating / pressurizing step includes at least the resin of the constraining yarn. It is the process of heating above the melting point.

  Such a heating / pressurizing step contributes to suppression of deviation in the arrangement of continuous fibers for resin reinforcement.

  The present invention has an excellent effect that the productivity of a fiber structure for resin reinforcement and the productivity of a fiber reinforced composite material can be increased.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiments of the invention will be described below with reference to FIGS.
As shown in FIG. 1 (a), the fiber structure 11 includes a plurality of reinforcing fiber layers 12, 13, 14, 15 composed of fiber bundles 121, 131, 141, 151 for resin reinforcement, and a thermoplastic resin. A plurality of resin fiber layers 16, 17, 18, 19, 20 including fiber bundles 161, 171, 181, 191, 201, a retaining thread 21, and a restraining thread 22 are included. The retaining thread 21 and the restraining thread 22 are made of a thermoplastic resin. The fiber bundles 121 to 151 for resin reinforcement, the fiber bundles 161 to 201 made of thermoplastic resin, the retaining yarn 21 and the restraining yarn 22 are made of continuous fibers.

  The reinforcing fiber layers 12, 13, 14, and 15 are disposed between adjacent thermoplastic resin resin fiber layers 16, 17, 18, 19, and 20, and the outermost layer of the fiber structure 11 is made of resin fibers. Layer 16 and resin fiber layer 20. The restraining yarn 22 penetrates the fiber structure 11 in the thickness direction of the fiber structure 11, and the restraining yarn 22 is folded back so as to straddle the retaining yarn 21 on the outside of the resin fiber layer 16. That is, the binding yarn 22 bonds the reinforcing fiber layers 12 to 15 and the resin fiber layers 16 to 20 in a laminated state.

  As shown in FIG. 1B, the fiber bundle 121 is aligned in one direction. That is, the fiber bundles 121 are arranged so that their length directions are aligned in the same direction indicated by the arrow X (hereinafter referred to as the X direction). The fiber bundles 131 are arranged so that the length direction thereof is aligned with the direction of an arrow B1 (hereinafter referred to as the B1 direction) that is oblique to the length direction (X direction) of the fiber bundle 121. The fiber bundles 141 are arranged so that the length direction thereof is aligned with the direction of the arrow Y (hereinafter referred to as the Y direction) orthogonal to the length direction (X direction) of the fiber bundle 121. The fiber bundles 151 are arranged so that the length direction thereof is aligned with the direction of an arrow B2 that is oblique to the length direction X of the fiber bundle 121 (hereinafter referred to as the B2 direction).

  The fiber bundles 161, 171, 181, and 191 are arranged so that the length direction thereof is aligned in the same direction X as the length direction of the fiber bundle 121, and the fiber bundle 201 is aligned in the length direction Y. Are arranged as follows.

  As the fiber bundles 121 to 151, fiber bundles such as carbon fibers, glass fibers, and aramid fibers are used. As the thermoplastic resin that is the material of the resin fiber layers 16 to 20, the retaining thread 21, and the restraining thread 22, polyethylene, polypropylene, nylon, or the like can be used.

FIG.1 (d) is a flowchart of the manufacturing process (including the manufacturing process of the fiber structure 11) of a fiber reinforced composite material. The lamination process will be described below.
As shown in FIG. 2 (a), the resin fiber layer 16 is formed by folding and engaging the fiber bundle 161 with a large number of pins 24 erected on the rectangular frame body 23 at a predetermined pitch and aligning them in the X direction. It is formed. After the resin fiber layer 16 is formed, the reinforcing fiber layer 12 is formed on the resin fiber layer 16 by causing the fiber bundle 121 to be folded back and engaged with the pins 24 in the X direction as shown in FIG. 2B. Is done. After the formation of the reinforcing fiber layer 12, as shown in FIG. 2C, the resin fiber layer 17 is formed by causing the fiber bundles 171 to be folded and engaged with the pins 24 to be aligned in the X direction.

  After the formation of the resin fiber layer 17, as shown in FIG. 3A, the reinforcing fiber layer 13 is formed on the resin fiber layer 17 by causing the fiber bundle 131 to be folded and engaged with the pins 24 and aligned in the B1 direction. Is done. After the formation of the reinforcing fiber layer 13, as shown in FIG. 3B, the resin fiber layer 18 is formed by causing the fiber bundle 181 to be folded and engaged with the pins 24 to be aligned in the X direction. After the formation of the resin fiber layer 18, as shown in FIG. 3C, the reinforcing fiber layer 14 is formed on the resin fiber layer 18 by causing the fiber bundle 141 to be folded and engaged with the pins 24 and aligned in the Y direction. Is done.

  After the formation of the reinforcing fiber layer 14, as shown in FIG. 4A, the resin fiber layer 19 is formed on the reinforcing fiber layer 14 by causing the fiber bundle 191 to be folded and engaged with the pins 24 and aligned in the X direction. Is done. After the formation of the resin fiber layer 19, as shown in FIG. 4B, the reinforcing fiber layer 15 is formed by folding and engaging the fiber bundle 151 with the pin 24 and pulling it in the B2 direction. After the formation of the reinforcing fiber layer 15, as shown in FIG. 4C, the resin fiber layer 20 is formed on the reinforcing fiber layer 15 by causing the fiber bundle 201 to be folded and engaged with the pins 24 and aligned in the Y direction. Is done.

Thus, the lamination process is completed.
Next, the insertion process will be described.
For example, it is inserted into the resin fiber layers 16 to 20 and the reinforcing fiber layers 12 to 15 on which the constraining yarn 22 is laminated by a method disclosed in Japanese Patent Application Laid-Open No. 8-218249. That is, the insertion needle is inserted in the stacking direction of the fiber layers 12 to 20 (the direction indicated by the arrow Z in FIG. 1A) with the restraining thread 22 locked in the hole at the tip of the insertion needle. The insertion needle is advanced to a position where the hole passes through the resin fiber layer 16. Thereafter, the insertion needle is slightly retracted, and the restraining thread 22 is in a state of forming a U-shaped loop. Next, the retaining thread needle is stopped when it passes through the U-shaped loop of the restraining thread 22 and reaches the ends of the fiber layers 12 to 20. At this time, the retaining thread 21 is locked to the tip of the retaining thread needle. Then, the retaining thread needle is pulled back, and the retaining thread 21 is inserted into the U-shaped loop of the restraining thread 22. In this state, the insertion needle is pulled back. Thereby, the retaining thread 21 is fastened by the restraining thread 22, and the fiber structure 11 is manufactured.

Thus, the insertion process is completed.
The manufactured fiber structure 11 is put into a fixed mold of a heatable press mold (not shown) having a fixed mold and a movable mold (arrangement step).

  The fiber structure 11 placed in the press die is heated and pressurized by a movable press operation (heating / pressurizing step). The heating temperature in this case is equal to or higher than the melting temperature (melting point) of the thermoplastic resin that is the material of the resin fiber layers 16 to 20, the retaining yarn 21, and the restraining yarn 22.

  When the time when the resin fiber layers 16 to 20 are considered to be completely melted elapses, the heated and pressurized fiber structure 11 is cooled in the press mold (cooling step). When the fiber structure 11 that has been heated and pressurized is cooled and the thermoplastic resin is solidified, a fiber-reinforced composite material 11A shown in FIG. 1C is formed. P in FIG.1 (c) shows the thermoplastic resin which the resin fiber layers 16-20, the retainer thread | yarn 21, and the restraint thread | yarn 22 fuse | melted and solidified.

In the present embodiment, the following effects can be obtained.
(1) The insertion needle of the restraining yarn 22 is easy to insert the laminated structure of the resin fiber layers 16 to 20 and the reinforcing fiber layers 12 to 15. Moreover, the resin fiber layers 16 to 20 are made of continuous fibers (fiber bundles 161 made of thermoplastic resin in the process of forming the reinforcing fiber layers 12 to 15 by arranging continuous fibers (fiber bundles 121 to 151) for resin reinforcement. ˜201) can be formed and the resin fiber layers 16-20 can be easily formed. Therefore, the productivity of the fiber structure 11 is improved.

  (2) In the configuration in which the outermost layer of the fiber structure 11 is the resin fiber layers 16 and 20, a fiber reinforced composite material 11A obtained by melting thermoplastic resin fibers (fiber bundles 161 to 201) in a press die. It is possible to smooth the surface.

  (3) In the configuration in which the restraining yarn 22 and the retaining yarn 21 are made of a thermoplastic resin, the restraining yarn 22 and the retaining yarn 21 are also formed when the resin fiber layers 16 to 20 are melted to form the fiber reinforced composite material 11A. Since it melts, the smoothness of the surface of the fiber-reinforced composite material 11A increases.

(4) The method of manufacturing the fiber reinforced composite material 11A by heating and pressurizing the fiber structure 11 advantageous for productivity increases the productivity of the fiber reinforced composite material 11A.
In the present invention, the following embodiments are also possible.

  In the above-described embodiment, the melting temperature (melting point) of the thermoplastic resin that is the material of the restraining yarn 22 is higher than the melting temperature (melting point) of the thermoplastic resin that is the material of the resin fiber layers 16 to 20. The type of the thermoplastic resin that is the material of the resin fiber layers 16 to 20 may be different from the type of the thermoplastic resin that is the material of the binding yarn 22. In this way, even after the resin fiber layers 16 to 20 are melted, the binding yarn 22 is not melted for a while. This is for maintaining the length direction of the fibers of the reinforcing fiber layers 12 to 15 after melting the resin fiber layers 16 to 20 in a predetermined direction (X direction, Y direction, B1 direction or B2 direction). It is valid. If the length direction of the fibers of each reinforcing fiber layer 12-15 is not maintained in a predetermined direction, the desired fiber-reinforced composite material 11A by defining the length direction of the fibers of each reinforcing fiber layer 12-15 The physical properties cannot be secured.

  It is more preferable that the melting temperature (melting point) of the thermoplastic resin that is the material of the retaining thread 21 is higher than the melting temperature (melting point) of the thermoplastic resin that is the material of the resin fiber layers 16 to 20.

  When polypropylene is adopted as the thermoplastic resin that is the material of the resin fiber layers 16 to 20, nylon can be adopted as the thermoplastic resin that is the material of the restraining yarn 22 and the retaining yarn 21.

The outermost layer of the fiber structure may be a reinforcing fiber layer.
The length direction of the fibers may be different, and the resin fiber layer may not be interposed between a pair of adjacent reinforcing fiber layers.

A pair of adjacent reinforcing fiber layers may have the same fiber length direction, and a resin fiber layer may be interposed between the pair of reinforcing fiber layers.
O The length direction of the fibers of all the resin fiber layers may be unified in the same direction (for example, any one of the X direction, the Y direction, the B1 direction, or the B2 direction).

The fiber length direction of the resin fiber layer may be the B1 direction or the B2 direction.
In the case where it is desired to strengthen the bond between the reinforcing fiber layers, the material of the bonding yarn may be the same fiber as the resin reinforcing fiber (carbon fiber, glass fiber, aramid fiber, etc.).

○ The material of the retaining thread may be the same quality as the resin reinforcing fiber (carbon fiber, glass fiber, aramid fiber, etc.).
The technical idea that can be grasped from the above-described embodiment will be described below together with the effects thereof.

[1] The fiber structure according to claim 5, wherein the retaining thread is made of a thermoplastic resin.
If the retaining thread is also made of a thermoplastic resin, the smoothness of the surface of the resin fiber layer is enhanced.

Embodiment is shown, (a) is a sectional side view of a fiber structure. (B) is a schematic diagram for showing the length direction of the fiber of a fiber layer. (C) is a sectional side view of a fiber reinforced composite material. (D) is a flowchart which shows the manufacturing method of a fiber structure, and the manufacturing method of a fiber reinforced composite material. (A), (b), (c) is a top view for demonstrating formation of a resin fiber layer and a reinforced fiber layer. (A), (b), (c) is a top view for demonstrating formation of a resin fiber layer and a reinforced fiber layer. (A), (b), (c) is a top view for demonstrating formation of a resin fiber layer and a reinforced fiber layer.

Explanation of symbols

  11 ... Fiber structure. 11A: Fiber reinforced composite material. 12-15 ... Reinforcing fiber layer. 121-151 ... Fiber bundles that are continuous fibers. 16-20 ... Resin fiber layer. 161-201 ... Fiber bundles that are continuous fibers. 21 ... Retaining thread. 22: Restraint thread.

Claims (10)

In a fiber structure for resin reinforcement used to produce a fiber-reinforced composite material in which resin is reinforced with fibers,
A reinforcing fiber layer composed of continuous fibers;
A resin fiber layer composed of continuous fibers made of thermoplastic resin;
A fiber structure comprising a constraining yarn for binding the laminated reinforcing fiber layer and the resin fiber layer.   The fiber structure according to claim 1, wherein the outermost layer of the fiber structure is the resin fiber layer.   The fiber structure according to any one of claims 1 and 2, wherein the binding yarn is made of a thermoplastic resin.   The fiber structure according to claim 3, wherein a melting point of the resin of the binding yarn is higher than a melting point of the resin fiber layer.   The fiber structure according to any one of claims 1 to 4, further comprising a retaining thread that engages with the restraining thread. In a method for producing a fiber structure for resin reinforcement used for producing a fiber-reinforced composite material in which resin is reinforced with fibers,
A laminating step of laminating the reinforcing fiber layer and the resin fiber layer;
An insertion step of inserting a constraining yarn so as to bond the laminated reinforcing fiber layer and the resin fiber layer;
The reinforcing fiber layer is formed by arranging continuous fibers, and the resin fiber layer is a method for producing a fiber structure formed by arranging continuous fibers made of thermoplastic resin.   The method for producing a fiber structure according to claim 6, wherein the constraining yarn is made of a thermoplastic resin.   The method for producing a fiber structure according to claim 7, wherein a melting point of the resin of the binding yarn is higher than a melting point of the resin fiber layer. In the manufacturing method of the fiber reinforced composite material in which the resin is reinforced by the fiber structure,
A laminating step of laminating the reinforcing fiber layer and the resin fiber layer;
An insertion step of inserting a constraining yarn so as to bond the laminated reinforcing fiber layer and the resin fiber layer;
An arrangement step of arranging the fiber structure manufactured through the insertion step in a mold;
A heating / pressurizing step of performing pressurization and heating in the mold;
A method for producing a fiber-reinforced composite material, comprising: a cooling step for cooling the heated and pressurized fiber structure.   The constraining yarn is made of a thermoplastic resin, and the melting point of the resin of the constraining yarn is higher than the melting point of the resin fiber layer, and the heating / pressurizing step is heated to at least the melting point of the resin of the constraining yarn. The method for producing a fiber-reinforced composite material according to claim 9, wherein the method is a step of:

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