JP5990030B2 - Method for molding fiber reinforced plastic structure and method for producing reinforced fiber sheet for VaRTM - Google Patents

Description

The present invention relates to an FRP structure molding method for producing a large fiber reinforced plastic (FRP) structure used in, for example, windmill blades, vehicles, ships, etc., by the RTM method, particularly the VaRTM method with vacuuming. Is. Moreover, this invention relates to the manufacturing method of the reinforced fiber sheet for VaRTM for using for such a FRP structure molding method.

  The VaRTM method is characterized by the use of dry (non-impregnated) reinforcing fiber sheets that do not contain resin, and are laminated in advance according to the shape of the product, sewed, or fused in the necessary direction. The product is shaped so that it has the necessary strength (preform). For example, it is put into a mold, or sealed with a film, vacuumed to inject and cure the resin, and then removed from the mold. This is the construction method.

  Currently, a large FRP structure (molded body) used for, for example, a windmill blade, a vehicle, a ship, and the like is manufactured by the VaRTM method, but a large FRP structure is manufactured by the VaRTM method. In some cases, it is necessary that the injected resin has good fluidity.

  In this respect, the reinforcing fiber sheet as described in Patent Document 1, that is, the strand sheet, is impregnated with matrix resin R in reinforcing fiber (generally carbon fiber) f as shown in FIG. A plurality of hardened continuous fiber reinforced plastic wires 2 having a small diameter are arranged in a slender shape in the longitudinal direction, and each wire 2 is fixed to each other with a wire fixing material 3. There is a gap (g) of 0 to 10 mm between the two, and when used for molding an FRP structure by the VaRTM method, the fluidity of the injected resin is good and the moldability is excellent.

JP 2004-197325 A

  However, in the strand sheet 1A as described in Patent Document 1, as shown in FIGS. 1A and 1B attached to the present application, the fiber reinforced plastic wire 2 constituting the strand sheet 1A is generally The FRP structure using the sheet 1A has a carbon fiber content Vf (Vf: the cross-sectional area ratio of the carbon fiber per unit cross-sectional area). It is difficult to raise the value. Further, the strand sheet 1A is more expensive than the unidirectional carbon fiber sheet 1B produced by aligning the carbon fibers f in one direction as shown in FIG. 2A attached to the present application.

  On the other hand, the carbon fiber sheet 1B produced by aligning the carbon fibers in one direction can be manufactured at a lower cost than the strand sheet 1A. However, when the fiber sheet 1B is used for molding an FRP structure by the VaRTM method, the strand sheet 1A is used. Compared with the case where it is used, the fluidity of the injected resin is poor, so that the impregnation property is poor, and the molding productivity is poor.

An object of the present invention is to provide an FRP structure molding method and VaRTM which can improve the resin impregnation property and improve the molding productivity in the molding of an FRP structure by the VaRTM method by increasing the fluidity of the injected resin. It is providing the manufacturing method of a reinforced fiber sheet.

Another object of the present invention is to make it possible to increase the Vf of reinforcing fibers (cross-sectional area ratio of reinforcing fibers per unit cross-sectional area) as compared with molding by a strand sheet, and to improve the bending strength and the like. It is providing the manufacturing method of the FRP structure molding method and the reinforcement fiber sheet for VaRTM.

The above object is achieved by the method for molding an FRP structure and the method for producing a reinforcing fiber sheet for VaRTM according to the present invention. In summary, according to the first aspect of the present invention, the reinforcing fiber sheet is arranged in a predetermined shape, sealed with an upper mold frame or a film, and a resin is injected into the reinforcing fiber sheet under vacuum to be cured. In the fiber reinforced plastic structure molding method by the VaRTM method for molding a reinforced plastic structure,
The reinforcing fiber sheet is
(A) a continuous plurality of continuous fiber-reinforced plastic wire plurality of reinforcing fibers in the matrix resin is a substantially circular cross-sectional shape or a flat sectional shape is cured impregnated, between the respective wire rods 0.2 A strand sheet formed by providing a gap (g) of 10 mm and aligning in a slender shape in the longitudinal direction;
(B) a plurality of continuous reinforcing fibers, a unidirectional reinforcing fiber sheet not impregnated with a resin formed into a sheet by aligning in one direction;
The strand sheet and the unidirectional reinforcing fiber sheet are pressed and integrated toward each other, and the unidirectional reinforcing fiber sheet is formed in the gap (g) portion of the fiber reinforced plastic wire of the strand sheet. There is provided a method for molding a fiber-reinforced plastic structure, characterized in that at least a part of the reinforcing fibers are contained therein. According to one embodiment of the present method, the injected resin has a viscosity at the time of resin injection of 30 to 300 mPa · s. According to another embodiment, the injection resin is an epoxy resin, a polyester resin, a vinyl ester resin, an MMA resin, an unsaturated polyester resin, or a phenol resin.

According to the second aspect of the present invention, the reinforcing fiber sheet is arranged in a predetermined shape, hermetically sealed with an upper mold or a film, and evacuated to inject the resin into the reinforcing fiber sheet and harden the fiber-reinforced plastic structure. A method for producing the reinforcing fiber sheet used in the VaRTM method of molding
(A) a continuous plurality of continuous fiber-reinforced plastic wire plurality of reinforcing fibers in the matrix resin is a substantially circular cross-sectional shape or a flat sectional shape is cured impregnated, between the respective wire rods 0.2 A strand sheet formed by providing a gap (g) of 10 mm and aligning in a slender shape in the longitudinal direction;
(B) a plurality of continuous reinforcing fibers, a unidirectional reinforcing fiber sheet not impregnated with a resin formed into a sheet by aligning in one direction;
The strand sheet and the unidirectional reinforcing fiber sheet are pressed and integrated toward each other, and the unidirectional reinforcing fiber sheet is formed in the gap (g) portion of the fiber reinforced plastic wire of the strand sheet. There is provided a method for producing a reinforcing fiber sheet for VaRTM, wherein at least a part of the reinforcing fibers is pressed.

According to one embodiment of the first and second aspects of the present invention, the fiber reinforced plastic wire has a substantially circular cross-sectional shape having a diameter (d) of 0.5 to 4 mm, or is formed of the wire. When the width w, a thickness t, the cross-sectional area and S, 1 <(w / t ) ≦ 10, and, 0.2mm ² ≦ S ≦ 12.6mm ² substantially oval shape or a substantially rectangular shape is This is a flat cross-sectional shape. According to another embodiment, at least one surface of the unidirectional reinforcing fiber sheet is held by a wire fixing material, and the surface of the unidirectional reinforcing fiber sheet on the wire fixing material side of the strand sheet. They are integrated so as to face one side.

According to another embodiment of the first and second aspects of the present invention, the laminate of the strand sheet and the unidirectional reinforcing fiber sheet is integrated with at least one surface held by a wire fixing material. The Further, according to another embodiment, the wire fixing material is a mesh-like support made of yarns that are biaxially or triaxially oriented and coated with a resin on the surface, Or it is the weft which weaves or weaves orthogonally to the wire rod of the strand sheet and / or the reinforcing fiber of the unidirectional reinforcing fiber sheet, or is bonded or fused to the surface.

  According to the present invention, in molding of an FRP structure by the VaRTM method, the fluidity of the injected resin can be increased to improve the resin impregnation property, and the molding productivity can be improved. Further, according to the present invention, the reinforcing fiber content Vf (cross-sectional area ratio of reinforcing fibers per unit cross-sectional area) can be increased as compared with the molding of the FRP structure by the strand sheet, and the FRP structure can be pulled and bent. The strength can be increased.

It is a figure for demonstrating an example of a strand sheet, Fig.1 (a) is a perspective view of a strand sheet, FIG.1 (b), (c), (d) is sectional drawing of a fiber reinforced plastic wire. . Fig.2 (a) is a perspective view of a unidirectional reinforcing fiber sheet, and FIG.2 (b) shows an example of the reinforcing fiber bundle which comprises a unidirectional reinforcing fiber sheet. It is a perspective view explaining the other example of a strand sheet. 4A and 4B are perspective views for explaining another example of the strand sheet. FIGS. 5A, 5B, and 5C are views for explaining an example of a reinforcing fiber sheet (hybrid sheet) according to the present invention. FIGS. 6A and 6B are views for explaining another embodiment of the hybrid sheet according to the present invention. FIGS. 7A and 7B are views for explaining another embodiment of the hybrid sheet according to the present invention. FIG. 8A is a perspective view for explaining another embodiment of the hybrid sheet according to the present invention, and FIG. 8B is a sectional view of the hybrid sheet. It is a figure for demonstrating the preparation process of the hybrid sheet according to this invention, FIG.9 (a) is a perspective view of a strand sheet, FIG.9 (b) is a perspective view of a unidirectional reinforcing fiber sheet, FIGS. 9C and 9D are cross-sectional configuration diagrams of the hybrid sheet. FIGS. 10A and 10B are views for explaining another embodiment of the hybrid sheet according to the present invention. It is a schematic block diagram of one Example of the shaping | molding apparatus for implementing a VaRTM construction method. It is a schematic block diagram of the other Example of the shaping | molding apparatus for implementing a VaRTM construction method.

  Hereinafter, the FRP structure molding method, VaRTM reinforcing fiber sheet and FRP structure according to the present invention will be described in more detail with reference to the drawings.

Example 1
First, a method for molding an FRP structure according to the present invention will be described.

  The FRP structure molding method according to the present invention is characterized by a reinforced fiber content rate when a large FRP (fiber reinforced plastic) structure used for, for example, a windmill blade, a vehicle, a ship or the like is manufactured by the VaRTM method. The purpose is to use a reinforcing fiber sheet having a high Vf and good fluidity of the injected resin.

  In order to solve the problems of the strand sheet 1A as shown in FIG. 1A and the unidirectional reinforcing fiber sheet 1B as shown in FIG. As a result of conducting various research experiments, as shown in FIGS. 5A, 5B, and 5C, an integrated laminate formed by laminating a strand sheet 1A and a unidirectional reinforcing fiber sheet 1B. It has been found that the conventional problem can be solved by using the reinforcing fiber sheet 10 (also referred to as “hybrid sheet”).

  That is, as shown in FIG. 5 (a), the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B are laminated and pressed toward each other so as to be integrated with each other. As shown in FIG. 2, a hybrid sheet 10 in which a part of the reinforcing fibers f of the unidirectional reinforcing fiber sheet 1B is inserted between at least the fiber reinforced plastic wires 2 and 2 of the strand sheet 1A can be formed. FIG. 5 (b) shows a hybrid sheet 10 in which all of the reinforcing fibers f of the laminated unidirectional reinforcing fiber sheet 1B are integrated between the wires 2 and 2, and FIG. A hybrid sheet 10 in which a part of the reinforcing fibers f of the direction reinforcing fiber sheet 1B enters between the wires 2 and 2 is shown. That is, some of the reinforcing fibers f form the surface layer of the strand sheet 1A.

  The FRP structure using the hybrid sheet 10 formed in this way can increase the reinforcing fiber content Vf as compared with the FRP structure manufactured with the strand sheet 1A. Moreover, as will be understood from the results of experiments conducted by the inventors described later, the hybrid sheet 10 having such a configuration is excellent in that the resin flowability is not significantly reduced even when compared with the strand sheet 1A. It was found that the product exhibited circulation. The reason is that, particularly in the VaRTM method, the viscosity of the injection resin to be used is low (viscosity at the time of injection is 30 to 300 mPa). Therefore, the injection resin easily flows between the wires 2 and 2 and is injected. Is done. This resin is considered to flow because of the capillary phenomenon caused by the carbon fibers f that have entered between the wires 2 and 2 and then between the carbon fibers f.

  The hybrid sheet 10 is not limited to the above configuration. For example, as shown to Fig.6 (a), (b), it can produce also by laminating | stacking the unidirectional reinforcement fiber sheet 1B on the both sides | surfaces of the strand sheet 1A, and pressing and integrating each other. it can. Alternatively, as shown in FIGS. 7A and 7B, the hybrid sheet 10 is also produced by laminating the strand sheets 1A on both side surfaces of the unidirectional reinforcing fiber sheet 1B and pressing the strand sheets 1A and 2B. be able to. Thus, the hybrid sheet 10 can also be configured by laminating three or more layers of the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B as desired.

  As understood above, the hybrid sheet 10 of the present invention is not only disposed in the gap (g) between the wires 2 and 2 as shown in FIG. As shown in FIGS. 6B and 7B, the unidirectional reinforcing fibers f are arranged on one side surface or both side surfaces of each wire 2 aligned in a slender shape. Can do.

  Next, the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B for producing the hybrid sheet 10 configured as described above will be described in more detail. In addition, although this invention is not limited, in the following description, as the reinforcing fiber of the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B, description will be made assuming that the most commonly used carbon fiber is used.

(Strand sheet)
In this embodiment, as shown in FIG. 1, the strand sheet 1A has a plurality of continuous fiber-reinforced plastic wires 2 having a small diameter, which are impregnated with a carbon resin f and cured with a matrix resin R, in a longitudinal direction. To align. Each wire 2 can also be fixed to each other by a wire fixing material 3. Each fiber-reinforced plastic wire 2 has a substantially circular cross-sectional shape with a diameter (d) of 0.5 to 4 mm, as shown in FIG. Further, as shown in FIGS. 1C and 1D, the wire 2 having a circular cross-sectional shape may be crushed from two directions, so-called flattened substantially oval or substantially rectangular. . Therefore, in this case, if the width of the wire 2 is w, the thickness is t, and the cross-sectional area is S, 1 <(w / t) ≦ 10. Further, flat shape wire 2 has a diameter (d) (i.e., d = 0.5 to 4 mm) because it is substantially the same cross-sectional area as the wire of, are 0.2mm ² ≦ S ≦ 12.6mm ^2.

Further, a gap (g) of 0.2 to 10 mm is provided between the wires 2 and 2. Incidentally, the gap (g) is necessary not Na is constant in the longitudinal direction of the wire 2.

When carbon fiber is used as the reinforcing fiber f, the fiber reinforced plastic wire 2 is impregnated with resin in a single fiber bundle in which 6000 to 60000 single fibers (carbon fiber monofilament) f having an average diameter of 7 μm are converged and cured. Is produced. The fiber basis weight of the strand sheet 1A is usually 200 to 2000 g / m ² .

  As described above, the hybrid sheet 10 according to the present invention is characterized in that, at least, the fiber reinforced plastic wire 2 arranged in the above-described fashioned shape is aligned in the gap (g) region between the two, and the carbon fiber is aligned in one direction. That is, the continuous unidirectional reinforcing fiber f is arranged. Thereby, the reinforcing fiber content Vf of the strand sheet 1A increases.

  The length (L) and width (W) of the strand sheet 1A thus obtained are appropriately determined according to the size and shape of the FRP structure to be produced. (W) is set to 100 to 1000 mm. Moreover, although the length (L) can manufacture a strip-shaped thing about 1-5 m, or a thing 100 m or more, it cuts and uses it suitably at the time of use.

  Further, the matrix resin R impregnated in the fiber reinforced plastic wire 2 is preferably a room temperature curing type or thermosetting type epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, or phenol resin. used. The fiber content (Vf) of the wire 1 is 40 to 75%, preferably 50 to 70%.

  Further, as a method of fixing each wire 2 with the wire fixing material 3, as shown in FIG. 1, for example, a plurality of wires arranged in a sag-like manner using wefts as the wire fixing material 3 are arranged. It is possible to adopt a method of driving and knitting a wire rod in the form of a sheet consisting of two, that is, a continuous wire rod sheet at a constant interval (P) perpendicular to the wire rod. Of course, as shown in FIG. 3, the weft 3 can be woven at a constant interval (P) between the wires. In any case, the driving distance (P) of the weft yarn 3 is not particularly limited, but is usually selected in the range of 10 to 100 mm in consideration of the handleability of the produced strand sheet 1.

  At this time, the weft 3 is a yarn obtained by bundling a plurality of glass fibers or organic fibers having a diameter of 2 to 50 μm, for example. As the organic fiber, nylon, vinylon, polyester or the like is preferably used.

  As another method of fixing each wire 2 in a slender shape, as shown in FIG. 4A, as a wire fixing material 3, for example, a mesh-like support made of glass fiber or organic fiber having a diameter of 5 to 20 μm. The body sheet 3 can be used.

  That is, the surface of the warp yarn 4 and the weft yarn 5 which are yarns such as glass fibers constituting the mesh support sheet as the wire fixing material 3 is impregnated in advance with a low melting point type thermoplastic resin, A plurality of wire rods 2 in which the support sheet 3 is aligned in a sheet form, that is, one side or both sides of the wire sheet are laminated and heated and pressed, and the warp yarn 4 and the weft yarn of the mesh-like support sheet 3 are pressed. The part 5 is welded to the wire sheet.

  In addition to the above biaxial configuration, the mesh-like support sheet 3 can also be formed by orienting yarns such as glass fibers in three axes. Moreover, it is also possible to adhere to the wire 2 that is arranged in a so-called uniaxial orientation and aligned in the sheet shape, in which only the wefts 5 orthogonal to the wire 2 arranged in one direction are arranged.

  As the thread of the wire fixing material 3, for example, a double-structured composite fiber having a glass fiber in the core and a low-melting-point heat-fusible polyester around it is also preferably used.

  Furthermore, as another method of fixing each wire 2 in a slender shape, as shown in FIG. 4 (b), as the wire fixing member 3, for example, a flexible belt material such as an adhesive tape or an adhesive tape is used. Can be used. The flexible strip 3 is a piece of a plurality of fiber reinforced plastic wires 2 that is perpendicular to the longitudinal direction of the fiber reinforced plastic wires 2 arranged in the form of a sheet and is perpendicular to the longitudinal direction, that is, perpendicular to the longitudinal direction. Affix the side or both sides. As the flexible strip 3, an adhesive tape or an adhesive tape having a width (w1) of about 1 to 10 mm, such as a vinyl chloride tape, a paper tape, a cloth tape, and a nonwoven fabric tape, is used. These tapes 3 are usually stuck in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 at intervals (P) of 10 to 100 mm. Furthermore, as the flexible strip 3, the thermoplastic resin such as nylon or EVA resin is formed into a strip and is heat-bonded to one side or both sides in the direction perpendicular to the longitudinal direction of the wire 2. Is done.

(Unidirectional carbon fiber sheet)
FIG. 2A shows an example of a unidirectional carbon fiber sheet 1B that can be used in the present invention. The unidirectional carbon fiber sheet 1B is a resin-unimpregnated unidirectional carbon fiber sheet configured in a sheet shape by aligning continuous carbon fibers f aligned in one direction in one direction. In addition, as shown in FIG.2 (b), the carbon fiber bundle F which converged the predetermined number of carbon fibers f with the cover thread | yarn 6 can also be produced as the unidirectional carbon fiber sheet 1B by aligning in one direction.

In addition, the unidirectional carbon fiber sheet 1B has a configuration in which a carbon fiber sheet composed of continuous carbon fibers f is held by the above-described wire rod fixing material 3 such as a mesh-like support sheet, similarly to the strand sheet 1A. It can also be. For example, when carbon fibers are used as the reinforcing fibers f, for example, a plurality of unimpregnated single fiber bundles in which 6000 to 60000 single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged in parallel in one direction. Used to align. The fiber basis weight of the carbon fiber sheet 1A is usually 200 to 2000 g / m ^2, and these are laminated and used.

  The surface of warp yarns 4 and weft yarns 5 which are yarns such as glass fibers constituting the mesh-like support material sheet as the wire fixing material 3 is impregnated with a low melting point type thermoplastic resin in advance, and the mesh-like support material The sheet 3 is laminated on one side or both sides of carbon fibers arranged in a sheet shape and heated and pressurized, and the warp 4 and weft 5 portions of the mesh-like support sheet 3 are welded to the carbon fiber sheet.

  In addition to the above biaxial configuration, the mesh-like support sheet 3 can also be formed by orienting yarns such as glass fibers in three axes. Alternatively, it is possible to adhere to the so-called uniaxially oriented carbon fiber in which only the wefts 5 orthogonal to the carbon fibers arranged in one direction are arranged.

  As the yarn of the wire fixing material 3, for example, a double-structured composite fiber having a glass fiber in the core and a low-melting-point heat-fusible polyester disposed around it is also preferably used.

  Further, as described with reference to FIGS. 1 and 3, the weft 5 can be knitted or woven in a direction orthogonal to the carbon fibers f arranged in one direction.

  In the description of the above embodiment, the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B have been described on the assumption that a plurality of fiber reinforced plastic wires 2 and a large number of reinforcing fibers f are fixed by the wire fixing material 3, respectively. However, the strand sheet 1A composed of only a plurality of fiber-reinforced plastic wires 2 that are not fixed by the wire rod fixing material 3 and arranged in a stale state, and the wire sheet fixing material 3 are aligned in one direction. It is also possible to form a hybrid sheet 10 by laminating using a unidirectional reinforcing fiber sheet 1B composed of a large number of reinforcing fibers f that are not fixed to each other and are in the form of a sheet only with a converging agent. It is. In this case, on the one side surface or both side surfaces of the integrated hybrid sheet 10 shown in FIGS. 5B, 5C, 6B, and 7B, for example, The wire fixing material 3 such as a resin-permeable mesh-like support can be bonded or fused. That is, the mesh-like support sheet is formed by orienting yarns made of glass fibers or the like in two or three axes, or by using only the weft yarn 5 and the resin coated on the yarn surface. It is bonded or fused to the outer surface of the hybrid sheet 10 which is a laminate with the unidirectional reinforcing fiber sheet. Of course, other wire fixing materials may be used. FIG. 8A shows an example in which the mesh-like support 3 is arranged on the unidirectional reinforcing fiber sheet side forming one side of the hybrid sheet 10 shown in FIG. FIG. 8B shows an example in which the wire fixing material 3 such as a mesh support is provided on both side surfaces of the hybrid sheet 10.

(Specific example of hybrid seat)
With reference to FIGS. 9A to 9D and FIGS. 10A and 10B, the hybrid sheet 10 is manufactured using the strand sheet 1A and the unidirectional carbon fiber sheet 1B having the above-described configuration. This will be described more specifically with reference to an example.

  9A and 9B show a strand sheet 1A and a unidirectional carbon fiber sheet 1B using a mesh-like support 3 as a wire fixing material. The mesh-like support 3 holds only one side of the strand sheet 1A and the unidirectional carbon fiber sheet 1B.

  Here, as shown in FIG. 9C, the strand sheet 1A and the unidirectional carbon fiber sheet 1B are arranged such that the other surfaces not held by the mesh-like support 3 are opposed to each other. Next, the strand sheet 1A and the unidirectional carbon fiber sheet 1B are laminated and pressed toward each other. As a result, as shown in FIG. 9 (d), the carbon fibers of the unidirectional carbon fiber sheet 1B are pushed between the wires 2 and 2 of the strand sheet 1A. The hybrid sheet 10 arranged as a surface layer on the side surface can also be produced. That is, the hybrid sheet 10 described with reference to FIGS. 5B and 5C is manufactured.

  Another example is shown in FIGS. 10 (a) and 10 (b). In this example, as shown in FIG. 10 (a), the unidirectional carbon fiber sheet 1B (1Ba, 1Bb) is used as the wire fixing material 3 in the same manner as the unidirectional carbon fiber sheet 1B shown in FIG. 9 (b). A unidirectional carbon fiber sheet having one surface held by the mesh support 3 is formed. Between the unidirectional carbon fiber sheets 1Ba and 1Bb, the strand sheet 1A is disposed and laminated.

  At this time, one unidirectional carbon fiber sheet 1Ba is disposed so that the other surface not held by the mesh-like support 3 faces, and the other unidirectional carbon fiber sheet 1Bb is a mesh-like support. 3 are arranged so that the other surfaces not held by 3 face each other. Next, the unidirectional carbon fiber sheet 1Ba, the strand sheet 1A, and the unidirectional carbon fiber sheet 1Bb are stacked and pressed toward each other. Thereby, as shown in FIG.10 (b), as for the unidirectional carbon fiber sheet 1Ba, the carbon fiber is pushed in between each wire 2 and 2 of the strand sheet 1A, and the surface of the other side of a strand sheet depending on the case. Also placed. On the other hand, the unidirectional carbon fiber sheet 1Bb is inhibited from being pushed between the wires 2 and 2 of the strand sheet 1A due to the mesh-like support 3. Therefore, a slight gap (v) is formed between the wire rods 2 and 2 of the strand sheet between the unidirectional carbon fiber sheet 1Bb and the strand sheet 1A. The gap (v) functions as a resin passage and improves the flow of the resin when the resin is injected at the time of VaRTM molding.

  In the example shown in FIGS. 10A and 10B, the unidirectional carbon fiber sheet 1Bb has been described as using a mesh-like support as the wire fixing material 3, but of course at least for the unidirectional carbon fiber sheet 1Bb Alternatively, the wire fixing material using only the weft 5 may be used, or the weft 5 may be knitted or woven at a predetermined interval perpendicular to the unidirectional carbon fiber sheet 1Bb. Of course, also in this case, as shown in FIG. 10 (b), there is a slight gap (v) between the wire rods 2 and 2 of the strand sheet between the unidirectional carbon fiber sheet 1Bb and the strand sheet 1A. It is formed. Moreover, it is not necessary to use the wire fixing material 3 for the unidirectional carbon fiber sheet 1Ba.

  Furthermore, as another example, as shown in FIG. 2 (b), as a unidirectional carbon fiber sheet 1 B, a carbon fiber bundle F in which a predetermined number of carbon fibers f are converged by a cover yarn 6 is aligned in one direction. When the produced one is used, it is difficult for the carbon fiber bundle F to be inserted between the wire rods 2 and 2 of the strand sheet 1A, and inevitably there is a slight gap (v) as shown in FIG. It will be formed between each wire 2 and 2 of the strand sheet 1A. As described above, this gap (v) serves to improve the flow of the resin when the resin is injected at the time of VaRTM molding.

  In the description of the above examples and specific examples, in the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B, the carbon fiber is used as the reinforcing fiber f. However, in addition to the carbon fiber, glass fiber, basalt fiber, etc. Inorganic fibers; Boron fibers, titanium fibers, steel fibers and other metal fibers; and organic fibers such as aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, polyarylate, polyester, and high-strength polyester alone. Or, it can be used in a hybrid by mixing plural kinds.

(VaRTM method)
When the hybrid sheet 10 having the above-described configuration is used for molding an FRP structure by the VaRTM method, the fluidity of the injected resin can be increased to improve the resin impregnation property, and the molding productivity can be improved.

  FIG. 11 shows a schematic configuration of an example of a molding apparatus 100 used in the VaRTM method. In this example, the molding apparatus 100 puts the hybrid sheet 10 into a mold (mold) 101, and a resin distribution medium 102 and a vacuum bag (film) 103 are set thereon. Resin R is injected between the resin distribution medium 102 and the mold 101 from the resin injection device 104 disposed adjacent to the mold 101. Further, the vacuum bag 103 is evacuated, whereby the hybrid sheet 10 is impregnated with the resin R. The carbon fiber sheet 10 impregnated with the resin R is heated together with the mold 101 with a heating device, for example, a heating plate or an oven, and the resin R is cured. Thereafter, the resin impregnated and cured hybrid sheet 10 is removed from the mold 101 to obtain a product (molded body of carbon fiber reinforced plastic structure). Of course, when a room-temperature curable resin R is used, a heating device or the like is unnecessary.

  FIG. 12 shows a schematic configuration of another example of the molding apparatus 100. In this example, the molding apparatus 100 is different in that an upper mold frame 101b is disposed instead of the film 103 in the molding apparatus 100 shown in FIG. That is, in the molding apparatus 100 of this example, the molding die 101 is configured by the lower mold frame 101a and the upper mold frame 101b, but the other configurations and functions are the same. Components having the same configuration and function are denoted by the same reference numerals, and the above description related to FIG. 11 is used, and detailed description is omitted. Of course, also in this example, when the room temperature curable resin R is used, a heating device or the like is unnecessary.

  Thus, according to the present invention, the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B constituting the hybrid sheet 10 which is a reinforcing fiber sheet are arranged in a predetermined shape and sealed with the upper mold frame 101b or the film 103, A fiber reinforced plastic structure molding method is provided by the VaRTM method in which a resin is injected into the hybrid sheet 10 under vacuum and cured to mold a fiber reinforced plastic structure.

Here, the reinforcing fiber sheet used as the hybrid sheet 10 is:
(A) a continuous plurality of continuous fiber-reinforced plastic wire plurality of reinforcing fibers in the matrix resin is a substantially circular cross-sectional shape or a flat sectional shape is cured impregnated, between the respective wire rods 0.2 A strand sheet 1A formed by providing a 10 mm gap (g) and aligning in a longitudinal manner in the longitudinal direction;
(B) a plurality of continuous reinforcing fibers, a unidirectional reinforcing fiber sheet 1B that is not impregnated with a resin and is formed into a sheet by aligning in one direction;
Are integrated, and at least a part of the reinforcing fibers f of the unidirectional reinforcing fiber sheet 1B enter the gap (g) of the fiber reinforced plastic wire 2 of the strand sheet 1A.

  Further, as the injection resin, VaRTM resin having a viscosity of 30 to 300 mPa · s at the time of resin injection is used.

  In this example, an epoxy resin was used as the VaRTM resin. In addition to the epoxy resin, a polyester resin having a viscosity of 30 to 300 mPa · s at the time of resin injection (temperature 25 ° C. as an example), Vinyl ester resin, MMA resin, unsaturated polyester resin, phenol resin, and the like can be used.

  As described above, the hybrid sheet 10 of the present invention is formed by laminating the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B and using them as a single unit, so that at least one fiber reinforced plastic wire 2 or 2 of the strand sheet 1A is provided. A reinforcing fiber sheet laminate in which a part of the reinforcing fibers f constituting the direction reinforcing fiber sheet 1B enters can be configured. Therefore, the hybrid sheet 10 of the present invention can increase the reinforcing fiber content Vf as compared to the strand sheet 1A. Thereby, according to this invention, compared with the shaping | molding of the FRP structure by 1 A of strand sheets, Vf (cross-sectional area ratio of the reinforced fiber per unit cross-sectional area) of a reinforced fiber can be made high, and the molded FRP structure The bending strength can be increased.

  Moreover, as described above, when the hybrid sheet 10 having such a configuration is used for molding an FRP structure by the VaRTM method, the fluidity of the injected resin is increased to improve the resin impregnation property, and the molding productivity is improved. Can be improved.

  Furthermore, since the unidirectional reinforcing fiber sheet 1B is soft and has no waist, the reinforcing fiber f is bent or wrinkled when used for molding a long molded FRP structure. For this reason, there is a concern that the performance of the reinforcing fiber f is lowered.

  On the other hand, the hybrid sheet 10 of the present invention includes the fiber reinforced plastic wire 2 and thus has a characteristic that it has a low waist, the fiber is difficult to bend, and is not easily wrinkled. Good performance.

Experimental Example In order to verify the working effect of the FRP structure molding method and VaRTM reinforcing fiber sheet (hybrid sheet) of the present invention, in Experimental Example 1, an experiment for evaluating the impregnation property of the hybrid sheet was performed. . In Experimental Example 2, it was confirmed by the bending performance of FRP whether the hybrid sheet of the present invention had a difference in performance compared to other sheets. Experimental examples 1 and 2 will be described below.

  The strand sheet 1A, the unidirectional carbon fiber sheet 1B, and the hybrid sheet 10 used in Experimental Examples 1 and 2 were produced as follows. In Experimental Examples 1 and 2, carbon fiber was used as the reinforcing fiber.

(Strand sheet 1A)
The strand sheet 1A was configured as shown in FIG. That is, the fiber reinforced plastic wire 2 uses carbon fibers as the reinforcing fibers f, and aligns a plurality of single fiber bundles in which 50,000 single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged in parallel in one direction. Arranged in a sheet. Each wire was impregnated with an epoxy resin and cured. Two types of wires were prepared so that the fiber basis weight of the strand sheet 1A was 1200 g / m ² and 800 g / m ² . As shown in Table 1 described later, those having a fiber basis weight of 1200 g / m ² were used for producing the hybrid sheet 10 as Example 1, and those having 800 g / m ² were used as Comparative Example 1. Each fiber reinforced plastic wire 2 had a substantially circular cross-sectional shape with a diameter (d) of 1.2 mm. Further, a gap (g) of 0.2 to 1.0 mm was provided between each wire 2 and 2.

  A biaxial mesh support sheet 3 was bonded to one side of each wire 2 in the form of a sheet.

  The carbon fiber sheet 10 thus produced had a width (W) of 200 mm and a length (L) of 100 m.

(Unidirectional carbon fiber sheet 1B)
The unidirectional carbon fiber sheet 1B has a configuration shown in FIG. That is, the unidirectional carbon fiber sheet 1B has a carbon fiber basis weight of 400 g / m of PAN-based carbon fiber strands (single fiber bundles) in which single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged and 24,000 converged numbers. ^They were arranged so as to be ² and arranged in a sheet form. A biaxial mesh support sheet 3 was bonded to one side of the sheet-like single fiber bundle.

  The carbon fiber sheet 1B thus produced had a width (W) of 200 mm and a length (L) of 100 m.

  As shown in FIGS. 9C and 9D, the hybrid sheet 10 has the strand sheet 1A and the unidirectional carbon fiber sheet 1B facing each other on the surface where the mesh-like support sheet 3 is not bonded. The hybrid sheet 10 was produced by laminating and pressing to form a single body.

Experimental example 1
The FRP board was produced for the hybrid sheet 10 of the above configuration, the strand sheet 1A, and the unidirectional carbon fiber sheet 1B by a VaRTM method using a VaRTM molding apparatus.

At this time, as shown in Table 1, as Example 1, two hybrid sheets 10 having the above-described configuration are used, and as Comparative Example 1, two strand sheets 1A having the above-described configuration are used. Used six unidirectional carbon fiber sheets 1B having the above-described configuration. As a result, the samples of Example 1 and Comparative Examples 1 and 2 all had a total basis weight of 2400 g / m ² .

  The molding apparatus 100 used in this experiment is an apparatus that implements the VaRTM method described with reference to FIG. 11, and the hybrid sheet 10 of Example 1 is inserted into a mold (molding mold) 101, and then the molding apparatus 100 is used. The resin distribution medium 102 and the vacuum bag 103 were set. The resin R was injected between the resin distribution medium 102 and the mold 101 from the resin injection device 104 disposed adjacent to the mold 101, and the vacuum bag 103 was evacuated. As a result, the hybrid sheet 10 was impregnated with the resin R. The carbon fiber sheet 10 impregnated with the resin R was heated by a heating device (oven) together with the mold 101, and the resin R was cured. Thereafter, the resin impregnated and cured hybrid sheet 10 was removed from the mold 101 to obtain a product (molded body of carbon fiber reinforced plastic structure). Similarly, each of the strand sheet 1A and the unidirectional carbon fiber sheet 1B of Comparative Examples 1 and 2 was used to produce an FRP structure (FRP plate) using the molding apparatus 100.

  The FRP plate thus obtained had a width of 200 mm × a length of 2 m, and the thickness was 2.2 mm in Example 1 and Comparative Example 2 as shown in Table 1, and 2.5 mm in Comparative Example 1. Met.

  Resin R used in Example 1 and Comparative Examples 1 and 2 is a low-viscosity VaRTM resin, an epoxy resin for composite materials manufactured by Nagase ChemteX Corporation (general-purpose type “XNR / H6815” (trade name) )It was used. The viscosity of the resin was 260 mPa · s / 25 ° C. and 80 mPa · s / 40 ° C. The viscosity at the time of pouring into the mold, that is, the resin viscosity at a temperature of 25 ° C. was 260 mPa · s.

In this experiment, when the hybrid sheet 10 of Example 1 was used and the total basis weight was 2400 g / m ² , the resin impregnation work was completed in about 0.5 hours (total molding work time 2.5 hours). And a good product could be obtained.

The strand sheet 1A of Comparative Example 1 was used to produce a product having a total basis weight of 2400 g / m ² as in Example 1. The resin impregnation work was more than that in the case of using the hybrid sheet 10 of Example 1. As soon as possible, it was completed in 0.25 hours (total molding work time 2.25 hours).

A product having a total basis weight of 2400 g / m ² similar to that of Example 1 was prepared using six unidirectional carbon fiber sheets 1B of Comparative Example 2, but the resin impregnation work was performed for 1.5 hours (total molding work). Time 3.5 hours).

Experimental example 2
In order to verify the effect of the FRP structure molding method and the reinforcing fiber sheet (hybrid sheet) of the present invention, in Experimental Example 2, the bending strength of the FRP structure when the hybrid sheet is used is evaluated. The experiment was conducted.

(Test method)
Using the same hybrid sheet 10, strand sheet 1A and unidirectional carbon fiber sheet 1B, resin, and experimental apparatus 100 as used in Experimental Example 1 shown in Table 1, Example 1, Comparative Examples 1 and 2 A FRP plate was prepared. The FRP plate was cut into a width of 10 mm and a length of 120 mm to prepare a bending test sample, and a three-point bending test by the JISK7203 method was performed. The test results are shown in Table 1.

  As can be understood from Table 1 as a result of the experiment, Example 1 and Comparative Example 2 have fewer voids and higher Vf (carbon fiber content) than Comparative Example 1, so that bending of the FRP plate is performed. Stress is high. On the other hand, in Comparative Example 1, since there is a gap (g) between the wires of the strand sheet, as described in Experimental Example 1, the resin impregnation property is good, but Vf is lower than the others, and the bending stress is low. I understand.

  As described above, the hybrid sheet 10 of the present invention is formed by laminating the strand sheet 1A and the unidirectional reinforcing fiber sheet 1B and using them as a single unit, so that at least one fiber reinforced plastic wire 2 or 2 of the strand sheet 1A is provided. A reinforcing fiber sheet laminate in which a part of the reinforcing fibers f constituting the direction reinforcing fiber sheet 1B enters can be configured. Therefore, the hybrid sheet 10 of the present invention can increase the reinforcing fiber content Vf as compared to the strand sheet 1A. Thereby, according to this invention, compared with the shaping | molding of the FRP structure by 1 A of strand sheets, Vf (cross-sectional area ratio of the reinforced fiber per unit cross-sectional area) of a reinforced fiber can be made high, and the molded FRP structure The bending strength can be increased.

  Moreover, when the hybrid sheet 10 having such a configuration is used for molding an FRP structure by the VaRTM method, the fluidity of the injected resin is increased to improve the resin impregnation property, and the molding productivity can be improved. it can. In addition, the hybrid sheet 10 of the present invention has the features that the fiber is reinforced because the fiber reinforced plastic wire 2 is contained, and the fibers are difficult to bend and become wrinkled, and the productivity is high and the performance is exhibited. Good sex.

DESCRIPTION OF SYMBOLS 1A Strand sheet 1B Unidirectional reinforcing fiber sheet 2 Fiber reinforced plastic wire material 3 Wire material fixing material 4 Warp yarn 5 Weft yarn 10 Hybrid sheet (reinforced fiber sheet)

Claims (10)

Fiber reinforced plastic by VaRTM method in which reinforced fiber sheets are arranged in a predetermined shape, sealed with an upper mold or film, vacuumed to inject resin into the reinforced fiber sheets and cured to form a fiber reinforced plastic structure In the structure molding method,
The reinforcing fiber sheet is
(A) a continuous plurality of continuous fiber-reinforced plastic wire plurality of reinforcing fibers in the matrix resin is a substantially circular cross-sectional shape or a flat sectional shape is cured impregnated, between the respective wire rods 0.2 A strand sheet formed by providing a gap (g) of 10 mm and aligning in a slender shape in the longitudinal direction;
(B) a plurality of continuous reinforcing fibers, a unidirectional reinforcing fiber sheet not impregnated with a resin formed into a sheet by aligning in one direction;
The strand sheet and the unidirectional reinforcing fiber sheet are pressed and integrated toward each other, and the unidirectional reinforcing fiber sheet is formed in the gap (g) portion of the fiber reinforced plastic wire of the strand sheet. A method for molding a fiber-reinforced plastic structure, wherein at least a part of the reinforcing fibers is contained. The fiber-reinforced plastic wire has a substantially circular cross-sectional shape with a diameter (d) of 0.5 to 4 mm, or if the width of the wire is w, the thickness is t, and the cross-sectional area is S, 1 < (w / t) ≦ 10, and fiber according to claim 1, characterized in that a substantially oval shape or a substantially rectangular flat cross section are 0.2mm ² ≦ S ≦ 12.6mm ² Reinforced plastic structure molding method.   At least one surface of the unidirectional reinforcing fiber sheet is held by a wire fixing material, and the wire fixing material side surface of the unidirectional reinforcing fiber sheet is opposed to one surface of the strand sheet. The fiber-reinforced plastic structure molding method according to claim 1, wherein the fiber-reinforced plastic structure is integrated.   The fiber-reinforced plastic structure molding method according to any one of claims 1 to 3, wherein the injected resin has a viscosity at the time of resin injection of 30 to 300 mPa · s.   5. The fiber-reinforced plastic structure molding method according to claim 4, wherein the injection resin is an epoxy resin, a polyester resin, a vinyl ester resin, an MMA resin, an unsaturated polyester resin, or a phenol resin. The reinforced fiber sheet is arranged in a predetermined shape, sealed with an upper mold or film, vacuumed, injected with resin into the reinforced fiber sheet and cured, and used in the VaRTM method of molding a fiber reinforced plastic structure. A method of manufacturing a reinforcing fiber sheet,
(A) a continuous plurality of continuous fiber-reinforced plastic wire plurality of reinforcing fibers in the matrix resin is a substantially circular cross-sectional shape or a flat sectional shape is cured impregnated, between the respective wire rods 0.2 A strand sheet formed by providing a gap (g) of 10 mm and aligning in a slender shape in the longitudinal direction;
(B) a plurality of continuous reinforcing fibers, a unidirectional reinforcing fiber sheet not impregnated with a resin formed into a sheet by aligning in one direction;
The strand sheet and the unidirectional reinforcing fiber sheet are pressed and integrated toward each other, and the unidirectional reinforcing fiber sheet is formed in the gap (g) portion of the fiber reinforced plastic wire of the strand sheet. A method for producing a reinforcing fiber sheet for VaRTM, wherein at least a part of the reinforcing fibers is pressed. The fiber-reinforced plastic wire has a substantially circular cross-sectional shape with a diameter (d) of 0.5 to 4 mm, or if the width of the wire is w, the thickness is t, and the cross-sectional area is S, 1 < (w / t) ≦ 10, and, VaRTM of claim 6, characterized in that a substantially oval shape or a substantially rectangular flat cross section are 0.2mm ² ≦ S ≦ 12.6mm ² Of manufacturing a reinforcing fiber sheet for a vehicle.   At least one surface of the unidirectional reinforcing fiber sheet is held by a wire fixing material, and the wire fixing material side surface of the unidirectional reinforcing fiber sheet is opposed to one surface of the strand sheet. The method for producing a reinforcing fiber sheet for VaRTM according to claim 6, wherein the reinforcing fiber sheet is integrated.   The laminated body of the strand sheet and the unidirectional reinforcing fiber sheet is integrally formed with at least one surface held by a wire fixing material and integrated with each other. Manufacturing method of fiber sheet.   The wire rod fixing material is a mesh-like support made of a yarn formed by being oriented biaxially or triaxially and having a surface coated with a resin, or the wire rod of the strand sheet and / or The weft yarn knitted perpendicularly to the reinforcing fiber of the unidirectional reinforcing fiber sheet, woven, or bonded or fused to the surface. A method for producing a reinforcing fiber sheet for VaRTM.

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