JP2006347133A - Marking method of reinforcing fiber substrate, manufacturing method of fiber-reinforced composite material, and fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a marking method of a reinforcing-fiber substrate capable of enhancing marking accuracy, a manufacturing method of a fiber-reinforced composite material with an excellent yield rate, and a fiber-reinforced composite material. <P>SOLUTION: A preform 1 is marked with folding lines 2, 3 (standard marks) which become standards when shaping and a positioning line 4 which becomes a standard (a standard mark) when positioning and arranging the preform 1 in a mold for shaping using thread shape fibers 5 having thermoplasticity by heatsealing the thread shape fibers 5 onto the surface of the preform 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for marking a reinforcing fiber substrate, a method for producing a fiber-reinforced composite material, and a fiber-reinforced composite material.

  Conventionally, a resin transfer molding method (hereinafter abbreviated as “RTM method”) has been adopted as one method for producing an FRP structure (a molded product of fiber reinforced plastic = fiber reinforced composite material). In the RTM method, a high-strength, high-modulus fiber reinforced fiber base material (hereinafter referred to as “preform”) that functions as a core is shaped into a predetermined shape, and then the preform is placed in a mold. In this method, a thermosetting resin is injected into the mold and impregnated into a preform, followed by heat curing to obtain an FRP structure.

By the way, in general, for the preform before shaping, there are a folding line as a reference when shaping the preform into a predetermined shape, a positioning line as a reference when placing the preform in the mold, etc. A reference line (reference mark) is marked. For example, in the marking method described in Patent Document 1, a positioning line is marked by hand with an oil marker pen on a preform made of dry cloth, and a reference line corresponding to the positioning line of the preform is marked in advance on the mold. I have to. Then, the preform is positioned and arranged in the molding die so that the positioning line marked on the preform and the reference line of the molding die are aligned.
JP 2003-127157 A

  However, in the above method, since the positioning line is marked by hand with an oil-based marker pen on a preform made of dry cloth, the marked positioning line may be blurred. In addition, when the preform is a fiber, the surface thereof is often an uneven surface. In such a case, the marked positioning line is distorted and the straightness of the line may be deteriorated. Therefore, if a line with poor marking accuracy that is blurred or distorted is used as the standard for various treatments for the preform (bending standard at the time of molding and positioning standard for the mold), the molding accuracy of the preform and the mold As a result, the yield of the molded FRP structure (fiber reinforced composite material) is reduced. Further, by marking with an oil-based marker pen, there is a possibility that the portion becomes a defect at the time of molding and leads to deterioration of physical properties.

  The present invention has been made in view of such circumstances, and its purpose is to provide a marking method for a reinforced fiber base material capable of improving marking accuracy, a method for producing a fiber reinforced composite material with good yield, and fiber reinforced. It is to provide a composite material.

  In order to achieve the above object, the invention according to claim 1 according to the marking method of the reinforcing fiber base is predetermined for the reinforcing fiber base as a core material of the fiber-reinforced composite material. The gist is to mark a fiducial mark as a fiducial mark when performing the treatment. According to this, compared with the case where the reference mark is marked with an oil-based marker pen or the like, the reference mark is not blurred and can be marked with high accuracy.

  The gist of the second aspect of the invention is the reinforcing fiber substrate marking method according to the first aspect, wherein the filamentous fibers are aromatic polyamide fibers. Since aromatic polyamide fibers have high strength and excellent heat resistance, according to the filamentous fibers made of such aromatic polyamide fibers, the fiducial marks are reliably marked stably on the reinforcing fiber substrate. be able to.

  The invention according to claim 3 is the gist of the reinforcing fiber substrate marking method according to claim 1, wherein the filamentous fibers are thermoplastic fibers and are thermally welded to the reinforcing fiber substrate. And According to this, even if the surface of the reinforcing fiber base is an uneven surface, it is possible to stably mark the reference mark and to improve the working efficiency because it can be marked in a short time.

  According to a fourth aspect of the present invention, there is provided the reinforcing fiber substrate marking method according to the third aspect, wherein the reinforcing fibers are stretched in a predetermined direction on the surface of the reinforcing fiber substrate. The gist is to heat-weld on the surface of the substrate. According to this, when the reference mark is a straight line having a predetermined length, it is easy to ensure the straightness of the reference mark, which is a more preferable marking mode.

  Moreover, the invention according to claim 5 relating to the method for manufacturing a fiber reinforced composite material is marked with a reference mark by the marking method for a reinforcing fiber substrate according to any one of claims 1 to 4. The reinforcing fiber base is placed in the mold using the fiducial mark as a reference for positioning and positioning with respect to the mold, and after the resin is injected into the mold and impregnated in the reinforcing fiber base, the resin is The gist is to produce a fiber-reinforced composite material by curing. According to this, since a preform with good marking accuracy can be used as a core material and the preform can be molded in a state where the preform is accurately positioned and placed in the mold, the yield of the manufactured FRP structure can be improved.

  According to a sixth aspect of the present invention, in the method for manufacturing a fiber-reinforced composite material according to the fifth aspect, the reinforcing fiber base is formed with reference to the reference mark before being placed in the mold. The gist is that it is shaped into a predetermined shape. According to this, since the shaping accuracy of the preform is good, the dimensional accuracy of the manufactured FRP structure can be maintained well.

  The gist of the invention according to claim 7 relating to the fiber-reinforced composite material is that it is manufactured by the method for manufacturing a fiber-reinforced composite material according to claim 5 or claim 6. According to this, since a preform with good marking accuracy is used as the core material, it is possible to obtain a fiber-reinforced composite material with a high yield and high dimensional accuracy.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1A, a preform (reinforced fiber base material) 1 used in this embodiment is a woven fabric, knitted fabric, or non-woven fabric made of glass fiber, carbon fiber, aramid fiber or the like having high strength and high elastic modulus. Or a three-dimensional woven fabric, a three-dimensional knitted fabric, a random mat, and the like, and the surface thereof has a fine uneven surface. In the present embodiment, the FRP structure (fiber reinforced composite material) 10 shown in FIG. 1D is manufactured by the resin transfer molding method (hereinafter referred to as “RTM method”) using the preform 1 as a core material. . That is, the FRP structure 10 is obtained by forming the preform 1 that has undergone the preform marking process (see FIG. 1B) and the preform shaping process (see FIG. 1C) into a molding die (molding) shown in FIG. Manufactured by the RTM method using a mold 20.

  In the preform marking step shown in FIG. 1 (b), a bending line (reference mark) 2 that serves as a reference at the time of shaping with respect to the preform 1 that has been cut into a predetermined shape (in this embodiment, a rectangular plate shape) in advance. , 3 and the preform 1 are marked with positioning lines (reference marks) 4 serving as a reference when the preform 1 is positioned in the molding die 20. In the preform shaping step shown in FIG. 1 (c), the marked preform 1 is folded along the folding lines 2 and 3, thereby forming the shape of the FRP structure 10 as a finished product (FIG. 1). 1 (d)) and substantially the same shape (see FIG. 1 (c)).

Hereinafter, the preform shaping process, the preform molding process, and the resin impregnation process will be described in detail with a focus on the preform marking process, which is the main part of the present invention.
First, in the preform marking process, as shown in FIG. 1B, the filamentous fibers 5 are parallel to the respective marking planned positions of the folding lines 2, 3 and the positioning line 4 on the surface of the preform 1. It is arranged. In addition, as the filamentous fiber 5 of the present embodiment, for example, a thermoplastic fiber such as triacetate, vinylon, nylon (registered trademark), polyvinyl chloride, polyester, acrylic, polypropylene, polyurethane, PBT (polybutylene terephthalate), or the like is used. Can do.

  In the present embodiment, the thread-like fiber 5 is predetermined by the clamp 6 on each marking planned position of the two folding lines 2 and 3 and the one positioning line 4 positioned between the two folding lines 2 and 3. Arranged in a stretched state. Then, the filamentary fibers 5 stretched on the preform 1 are pressed against the surface of the preform 1 from above by the heating roller 7. Then, since the filamentous fiber 5 is a thermoplastic fiber, it is melted by heating by the heating roller 7 and is thermally welded onto the surface of the preform 1. In this way, the two folding lines 2 and 3 and the one positioning line 4 are marked by the thread fibers 5 respectively. At this time, since the filamentous fiber 5 is heat-sealed in a stretched state, the filamentary fiber 5 is straightly marked without bending and the marking line being shaken.

  Next, in the preform shaping step, as shown in FIG. 1 (c), the preform 1 that has undergone the preform marking step is bent along the folding lines 2 and 3 into a substantially U-shaped cross section. . In addition, when shaping the preform 1 in the preform shaping step, a shaping device (not shown) is used.

  Next, in the preform molding step, the preform 1 is placed in the molding die 20. As shown in FIG. 2, the molding die 20 used in the present embodiment includes an upper die 21 and a lower die 22, and a recess 23 is formed on the upper surface of the lower die 22. When the upper mold 21 and the lower mold 22 are in contact with each other, that is, when the molding die 20 is clamped, the concave portion 23 is a cavity between the convex portion 24 formed on the lower surface of the upper mold 21. S is formed, and is formed in a size that allows the preform 1 to be accommodated and disposed (see FIGS. 2 and 3). 2 and 3, for the sake of clarity, the cavity S is illustrated as having a gap between the preform 1 and the inner wall of the cavity S. The preform 1 is accommodated without a gap.

  The lower mold 22 in the molding die 20 is formed with an injection path 25 for injecting a synthetic resin (in this embodiment, a thermosetting resin) into the cavity S from an unillustrated injection machine. Similarly, in the lower mold 22, the excess resin out of the synthetic resin injected into the cavity S from the injection path 25 is placed at a position opposite to the formation position of the injection path 25 across the recess 23. A discharge path 26 for discharging out of the cavity S is formed.

  Further, as shown in FIG. 3, on the upper surface of the lower mold 22, a position that is aligned with the positioning line 4 on the preform 1 side when the preform 1 is positioned in the recess 23 of the lower mold 22. Marks 27 and 28 are marked in two places. That is, the position marks 27 and 28 are formed at the intermediate position in the width direction of the recess 23. Therefore, by aligning both ends of the positioning line 4 on the preform 1 side with the position marks 27 and 28 on the lower mold 12 side and placing the preform 1 in the recess 23 of the lower mold 22, the preform 1 is positioned. The reform 1 can be accurately positioned at the center position in the molding die 20.

  Next, in the resin impregnation step, the upper mold 21 and the lower mold 22 are clamped in a state where the preform 1 is positioned and disposed in the recess 23 of the lower mold 22, and then the thermosetting resin is injected into the cavity S from the injection path 25. The preform 1 is impregnated. Further, the surplus resin overflowed from the thermosetting resin filled in the cavity S is discharged out of the cavity S through the discharge path 26. Then, after the thermosetting resin is completely cured in the cavity S, the molding die 20 is opened, and the FRP structure 10 is removed from the recess 23 of the lower die 22. The demolded FRP structure 10 is trimmed as necessary to obtain a finished product.

According to the embodiment described above, the following effects can be obtained.
(1) In the above embodiment, since the folding lines 2 and 3 and the positioning line 4 are marked on the preform 1 with the filamentous fiber 5, the marked lines 2 and 3 are compared with the case of marking with an oil marker pen or the like. The straightness of the line is ensured without blurring of 4. That is, the marking accuracy of each of the lines 2, 3, 4 with respect to the preform 1 is improved, whereby the shaping accuracy of the preform 1 and the positioning accuracy of the preform 1 with respect to the molding die 20 can be improved. . Furthermore, the yield of the FRP structure 10 manufactured using such a preform 1 as a core material can be improved.

  (2) In the above embodiment, since the yarn-like fibers 5 are heat-welded in a stretched state, the yarn-like fibers 5 are not bent during the heat-welding and the bending lines 2 and 3 and the positioning line 4 are not shaken. Good straightness of the line is ensured. Therefore, it becomes a more suitable marking mode in order to improve shaping accuracy and positioning accuracy.

  (3) Further, by marking the fiber-like fibers 5 on the surface of the preform 1 by a heat welding process, it is possible to stably mark the uneven surface 1 with a fine surface. Marking work can be performed in time, and work efficiency can be improved.

In addition, you may change the said embodiment into the following other embodiment (another example).
In the above embodiment, the thread-like fiber 5 may be a different color thread-like fiber for each of the folding lines 2 and 3 and the positioning line 4.

  In the above embodiment, the preform 1 may be one in which only the folding lines 2 and 3 are marked with the thread-like fibers 5, or only the positioning line 4 may be marked with the thread-like fibers 5. Good.

  In the above embodiment, the marking positions and the number of markings on the folding lines 2 and 3 may be one (one place) or three (three places) or more. Similarly, if the marking position and the number of markings of the positioning line 4 correspond to the position marks 27 and 28 formed on the lower mold 22 of the molding die 20, the marking position and the number of markings are two (two places) or more. Also good.

  In the above embodiment, the filamentous fibers 5 may be thermally welded on the surface of the preform 1 without being stretched. Further, when the thread-like fiber 5 is placed in a tensioned state, the tensioning means can be appropriately changed such that the operator grips it by hand in addition to the clip 6 described in the embodiment.

  O It is good also as a form which scoops the thread-like fiber 5 by manual work or a machine work, and marks the bending lines 2, 3 etc. on the preform 1. FIG. In this case, various synthetic fibers and natural fibers can be used for the filamentous fiber 5, but it is preferable to use an aromatic polyamide fiber, that is, an aramid fiber. Aramid fiber is a synthetic fiber that can be divided into “para-type”, which has high strength and excellent heat resistance, and “meta-type”, which has high flame resistance and high heat resistance, and is mainly composed of metaphenylenediamine and isophthalic acid chloride. It is an organic synthetic fiber that uses polymetaphenylene isophthalamide as a raw material. This aramid fiber is a chemically stable and spread benzene ring that is continuously bonded to the meta-type by an amide bond, so that existing synthetic fibers such as polyester and nylon (registered trademark) Maintains fiber performance (strong elongation, elastic modulus, specific gravity, texture, color, etc.) comparable to natural fibers. For example, it does not melt in the air, and has both heat resistance that starts decomposition and carbonization for the first time at 400 ° C., and flame resistance and flame retardancy of 29 or more of the limiting oxygen index (LOI value). Therefore, when an aramid fiber is used as a filamentous fiber, it is preferable because the marking line can be stabilized because it has high strength and excellent heat resistance compared to nylon (registered trademark) or the like. .

  ○ The marking method of the preform (reinforcing fiber substrate) of the above embodiment is not limited to the one applied to the preform 1 as the core material of the FRP structure 10 manufactured by the RTM method, and manufactured by other methods. You may apply to the preform as a core material of the FRP structure to be made.

  ○ In the manufacturing method of the FRP structure of the above embodiment, a thermoplastic resin may be used in the resin impregnation step.

It is a figure explaining the manufacturing process of a FRP structure centering on a preform marking process, (a) is a perspective view which shows the preform before marking, (b) is a schematic explanatory drawing of a preform marking process, (c) ) Is a perspective view showing a preform after shaping, and (d) is a perspective view showing a manufactured FRP structure. Sectional drawing of the metal mold | die for shaping | molding. The top view of the lower mold | type which has arrange | positioned the preform in a recessed part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Preform as a reinforced fiber base material, 2, 3 ... Bending line as a reference mark, 4 ... Positioning line as a reference mark, 5 ... Threaded fiber, 10 ... FRP structure as a fiber reinforced composite material, 20 ... Mold for molding as a mold.

Claims (7)

A method for marking a reinforcing fiber substrate, in which a fiducial fiber is used as a reference mark when a predetermined treatment is performed on the reinforcing fiber substrate, with respect to the reinforcing fiber substrate serving as a core material of the fiber-reinforced composite material. The method for marking a reinforcing fiber substrate according to claim 1, wherein the filamentous fibers are aromatic polyamide fibers. The method for marking a reinforcing fiber substrate according to claim 1, wherein the filamentous fiber is a thermoplastic fiber and is thermally welded to the reinforcing fiber substrate. The marking method for a reinforcing fiber substrate according to claim 3, wherein the filamentary fibers are thermally welded onto the surface of the reinforcing fiber substrate in a state in which the filamentary fibers are stretched in a predetermined direction on the surface of the reinforcing fiber substrate. A reinforcing fiber base material marked with a fiducial mark by the reinforcing fiber base material marking method according to any one of claims 1 to 4 is molded using the fiducial mark as a reference for positioning and positioning with respect to a mold. A method for producing a fiber-reinforced composite material, which is placed in a mold, injecting a resin into the mold and impregnating the reinforcing fiber substrate, and then curing the resin to produce a fiber-reinforced composite material. The method for producing a fiber-reinforced composite material according to claim 5, wherein the reinforcing fiber base is shaped into a predetermined shape with reference to the reference mark before being placed in the mold. The fiber reinforced composite material manufactured by the manufacturing method of the fiber reinforced composite material of Claim 5 or Claim 6.

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