JP4965296B2 - Preform and FRP manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a preform having a corner portion , and a method for manufacturing FRP (fiber reinforced plastic) using the preform manufactured by the method.

  A vacuum RTM (Resin Transfer Molding) that molds FRP by placing a dry reinforcing fiber base on a mold, covering the whole with a bag material, depressurizing the inside, and injecting resin into the reinforcing fiber base. ) A molding method is known (for example, Patent Document 1). In this vacuum RTM molding method, the reinforcing fiber base is usually shaped in advance into a predetermined shape, and the preform is placed on a mold. Further, a resin diffusion medium for uniformly diffusing the injected resin at the time of FRP molding, or a release layer for peeling the resin diffusion medium from the FRP after FRP molding (hereinafter sometimes referred to as peel ply). A molding method using a secondary material such as) is also known (Patent Document 1).

  However, when the FRP to be molded has a corner portion, and accordingly, when the preform of the reinforcing fiber base has a corner portion, the following problems may occur. For example, FIG. 2 shows an example when no secondary material is used, and FIG. 3 shows an example when a secondary material is used. In the example shown in FIG. 2, a reinforcing fiber base material 102 shaped into a shape having a corresponding corner portion is disposed in a female mold 101 having a corner portion, and a bagging film 103 (for example, a bag material as a whole) , Nylon film), and the inside is sealed with a sealing material 104 with respect to the outside (FIG. 2A). In this state, the inside is evacuated and resin is injected into the decompressed interior, and the reinforcing fiber base material 102 is impregnated with the resin (FIG. 2B). At this time, a pressing force is applied from the bagging film 103 to the reinforcing fiber base 102, but the reinforcing fiber base 102 stretches in a bridge shape at the corner portion. Is formed, the thickness of the gap is thicker than other parts, for example, thicker than the thickness B of the reinforcing fiber base 102 at the bottom part of the mold. When the resin is cured in this state and the FRP is molded, as shown in FIG. 2C, the molded FRP 105 similarly has a relationship of A ′ ≧ B ′ between the corresponding portions. Dimensional accuracy may not be obtained. Further, in the thick portion A ′, the volume content Vf of the reinforcing fiber may be reduced, a resin rich portion may be generated, or a void may be generated in some cases.

Further, in the example shown in FIG. 3, a reinforcing fiber substrate 112 shaped into a shape having a corresponding corner portion is disposed in a female mold 111 having a corner portion, and a peel ply 113 and a resin diffusion are formed thereon. A medium 114 (for example, a medium made of polypropylene) is sequentially arranged, and the whole is covered with a bagging film 115 (for example, a nylon film) as a bag material, and the inside is sealed with a sealing material 116 with respect to the outside (see FIG. 3 (A)). In this state, the inside is evacuated and resin is injected into the decompressed interior, and the reinforcing fiber base material 112 is impregnated while being diffused through the resin diffusion medium 114 (FIG. 3B). At this time, pressure is applied from the bagging film 115 to the reinforcing fiber base 112, but the auxiliary fiber base 112, the peel ply 113, and the auxiliary material of the resin diffusion medium 114 are stretched in a bridge shape at the corner portion. The thickness C of the reinforcing fiber base 112 becomes thicker or the gap 117 is formed, and becomes thicker than the thickness B of the reinforcing fiber base 112 at the bottom of the mold, for example. When the resin is cured and the FRP is molded in this state, as shown in FIG. 3C, the molded FRP 118 similarly has a relationship of C ′ ≧ B ′ between the corresponding portions. There is a risk that the dimensional system will not be obtained. Further, in the thick portion A ′, the volume content Vf of the reinforcing fiber is small, and in the portion where the gap 117 is formed, the resin rich portion 119 may be generated or a void may be generated in some cases.
JP 2004-130599 A

Therefore, the object of the present invention is to pay particular attention to the above-described problems in the corner portion, prevent the reinforcing fiber base material and the auxiliary material from bridging during FRP molding, and maintain the thickness in the corner portion at a predetermined thickness. to provide the corner portions to prevent the generation of resin rich portion and voids, a method of manufacturing a preform, a and FRP manufacturing method using the preform produced by the method.

In order to solve the above problems, a manufacturing method of a preform according to the present invention is formed by using a reinforcing fiber base material, a method of manufacturing a preform for FRP molding having a corner portion, the preform On the shaping jig having a corner portion corresponding to the corner portion, as a secondary material, a resin diffusion medium for diffusing the resin during FRP molding and a release layer for peeling the resin diffusion medium from the FRP after molding Arranged in this order, a reinforcing fiber base is placed with an adhesive material interposed between the sub-materials, and a pressure applied by the rubber sheet acts by covering the rubber sheet and depressurizing the inside. And, while integrating the auxiliary material and the reinforcing fiber base material through the adhesive material, after forming the integrated material along the shaping jig, release the pressure by the rubber sheet From By demolded foam comprises a method, wherein at least the over corner portions and side portions thereof of the preform, to shaping the preform into an integrated state with auxiliary materials to the reinforcing fiber base.

  That is, in the present invention, a preform having a corner portion is shaped as a preform having a predetermined shape in a state in which the auxiliary material is integrated with the reinforcing fiber base before being used for FRP molding. Since the reinforcing fiber base material and the auxiliary material are integrated with each other, they maintain each other in a predetermined shape, so that the occurrence of a bridge at the corner portion is prevented and the thickness of the reinforcing fiber base material increases at the corner portion. Is prevented, and a gap is prevented from being generated at the corner portion during molding, thereby preventing the occurrence of a resin rich portion and a void.

  More specifically, for example, on the shaping jig having a corner portion corresponding to the corner portion of the preform, the auxiliary material and the reinforcing fiber substrate are arranged with an adhesive material interposed therebetween, A pressure applied by the rubber sheet is applied to the auxiliary material and the reinforcing fiber base by covering the rubber sheet and reducing the inside, and the auxiliary material and the reinforcing fiber base are integrated via the adhesive material, The integrated material is shaped along the shaping jig. At the time of shaping, in addition to pressurization by a rubber sheet, heating of the integrated material can facilitate shaping and also promote integration by an adhesive material.

  After shaping the integrated material along the shaping jig, the pressure applied by the rubber sheet may be released. After releasing the pressure, the preform shaped into a predetermined shape is removed from the shaping jig. The mold may be removed and used for FRP molding.

Examples of the auxiliary materials, FRP molding peeling layer for resin distribution medium body for diffusing the resins and for peeling the resin distribution medium from the post-molding FRP during (i.e., peel ply described above) employs a structure comprising.

In the present invention, such a preform preform produced by the method for producing, i.e. preform reinforcing fiber base and auxiliary materials are integrated at least in the corner portion is provided.

  The FRP manufacturing method according to the present invention includes a preform manufactured by the above method placed on a molding die, the entire preform is covered with a bag material, the inside is decompressed, and a resin is applied to the preform. Consisting of a method of injecting.

  The FRP manufacturing method according to the present invention includes a preform manufactured by the method as described above, which is disposed in a female mold having a shape obtained by inverting the shape of the shaping jig, and the entire preform is disposed. It consists of a method in which the interior is decompressed by covering with a bag material and a resin is injected into the preform.

  In such an FRP manufacturing method, the relationship between the reinforcing fiber volume content Vpf (%) at the preform shaping stage and the reinforcing fiber volume content Vf (%) after FRP molding is Vf−5 ≦ Vpf ≦ Vf + 2. It is preferable that it exists in. Control within this range can be performed, for example, by setting and controlling the shaping temperature, the shaping pressure via the rubber sheet, and the holding time. This Vf (%) is the FRP design target value. When Vpf (%) is lower than Vf-5 (%), there is a high possibility that the same problem as shown in FIG. 3 will occur. When Vpf (%) is higher than Vf + 2 (%), FRP When Vpf is to be returned to Vf during molding, there is a high possibility that local wrinkles are likely to occur.

  According to the present invention, by forming a preform in which the reinforcing fiber base material and the auxiliary material are integrated, it is possible to prevent occurrence of a bridge between the reinforcing fiber base material and the auxiliary material at the corner portion during FRP molding. Prevents the increase in the thickness of the reinforcing fiber base and the generation of gaps at the corners, ensuring molding to the specified dimensions and preventing the generation of resin rich parts and voids. Thus, uniform FRP physical properties can be achieved.

  Further, the integration of the reinforcing fiber base material and the secondary material can prevent the secondary material from shifting during FRP molding. Furthermore, since it is not necessary to separately arrange the auxiliary materials at the time of FRP molding, foreign matter contamination (contamination) at the time of arranging the auxiliary materials or before the arrangement is eliminated, and contamination to the FRP molded product can be prevented. .

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a preform manufacturing method according to an embodiment of the present invention, and a series of steps until FRP is molded using the preform manufactured by the method. 1A and 1B show a preform manufacturing method according to an embodiment of the present invention. As shown in FIG. 1A, a male mold 2 as a shaping jig having a corner portion is provided on a base tool 1, and in this embodiment, hot water for heating is provided in the male mold 2. A piping 3 is buried. On the male mold 2 as the shaping jig, a resin diffusion medium 4 (for example, a polypropylene resin diffusion medium) as a secondary material and a peel ply 5 (for example, a nylon peel ply) as a release layer are arranged in this order. Further, a reinforcing fiber base material 7 (for example, a reinforcing fiber base material made of a laminate of a plurality of base materials) in which an adhesive material 6 (for example, a thermoplastic resin) is dispersed is disposed on the surface of the secondary material. The A rubber sheet 8 is placed thereon, and the periphery is sealed with a sealing material 9.

  In this state, as shown in FIG. 1 (B), the inside covered with the rubber sheet 8 is depressurized by vacuum suction by a vacuum pump (not shown) or the like, whereby the pressing force by the rubber sheet 8 is applied, The reinforcing fiber base 7 and the auxiliary material are shaped so as to be in close contact with the outer surface of the male mold 2 and are reinforced by the adhesive material 6 interposed between the reinforcing fiber base 7 and the auxiliary material. It is shaped as a preform 10 in which the fiber base material 7 and the auxiliary material are integrated. In this embodiment, at the time of shaping, the heat insulating cover 11 is disposed on the rubber sheet 8, warm water is passed through the hot water pipe 3, and heating is also performed, whereby the shaping of the preform 10 and the adhesive material are performed. The integration of the reinforcing fiber base 7 and the auxiliary material by 6 is promoted. When the predetermined shaping is completed, the preform 10 having the corner portion is removed from the male mold 2 to obtain the preform 10 according to the present invention.

  Using this preform 10, the FRP manufacturing method according to the present invention is carried out as shown in FIGS. 1 (C), (D), and (E). As shown in FIG. 1C, the preform 10 has a corner portion corresponding to the corner portion of the preform 10 (that is, has a shape obtained by inverting the shape of the male mold 2 as the shaping jig). These are placed in a female die 12 as a molding die, covered with a bagging film 13 as a bag material, and the periphery is sealed with a sealing material 14. In this state, as shown in FIG. 1D, the interior covered with the bagging film 13 is depressurized by vacuum suction using a vacuum pump (not shown) or the like, and the liquid that becomes the matrix resin of FRP is contained in the decompressed interior. The resin is injected and so-called vacuum RTM molding is performed. At the time of this vacuum RTM molding, the preform 10 is formed by integrating the reinforcing fiber base material 7 and the auxiliary material in advance, so that the shape, particularly the shape of the corner portion, corresponds to a predetermined molding target shape. The shape is maintained, and the reinforcing fiber base material 7 and the auxiliary material are prevented from stretching in a bridge shape at the corner portion. Therefore, the thickness E of the reinforcing fiber base 7 in the corner portion and the thickness of other portions, for example, the thickness D of the flat portion of the reinforcing fiber base 7 in the bottom of the female die 12 are kept substantially equal. It is. Further, in order to improve the surface property of the molded product, a curl plate may be arranged on the surface of the preform or on the auxiliary material.

  In the vacuum RTM molding, after the resin is cured, the bagging film 13 is removed, the molded body is removed from the female mold 12, and the peel ply 5 is peeled off to remove the peel ply 5 and the resin diffusion medium 4. An FRP 15 (FRP molded product) as shown in FIG. 1 (E) is obtained. As described above, since the thicknesses E and D of the reinforcing fiber base 7 at the time of vacuum RTM molding are kept equal, the thickness E ′ at the corner portion and the thickness D ′ at the bottom flat portion also in the FRP 15 after molding. The thickness is substantially equal, and the FRP 15 is finished to a target shape and size throughout.

  In this vacuum RTM molding, as described above, the reinforcing fiber volume content Vpf (%) of the reinforcing fiber base 7 in the shaping stage of the preform 10 and the reinforcing fiber volume content Vf (%) after the FRP molding. ) Is preferably in a relationship of Vf−5 ≦ Vpf ≦ Vf + 2. Control to this range is to appropriately set and control the shaping temperature by controlling the temperature of the hot water, appropriately set the shaping pressure force by the rubber sheet 8 by controlling the degree of vacuum by the vacuum suction, It can be easily performed by controlling. As described above, when Vpf (%) is lower than Vf-5 (%) with respect to Vf (%) which is the design target value of FRP 15, there is a possibility that the same problem as the conventional one shown in FIG. 3 may occur. If Vpf (%) is higher than Vf + 2 (%), there is a high possibility that local wrinkles are likely to occur when Vpf is returned to Vf during molding of FRP 15.

The reinforcing fiber volume content Vpf in this preform can be calculated as follows.
Vpf = W1 / (ρ × T1) × 100 (%)
here,
W1: Weight of reinforcing fiber per 1 cm ^{2 of} preform (g / cm ² )
ρ: Density of reinforcing fiber (g / cm ³ )
T1: Preform thickness measured in accordance with JIS R7602 under a load of 0.1 MPa (cm)
It is.

In order to achieve a high Vf in the FRP molded product, it is preferable that the Vpf in this preform is also high, and examples of preferable Vpf include a range of 45 to 60%. If it is less than 45%, the resin impregnation property in vacuum RTM molding is good, but the FRP has a small fiber volume content, and the mechanical properties of the FRP are also lowered accordingly. On the other hand, if it exceeds 60%, the gaps between the reinforcing fiber yarns and the fibers become small, and the resin hardly flows, which is not preferable. The measurement method of the reinforcing fiber volume content Vf of this molded product is based on ASTM D3171-99 (2004), and the thickness is measured using a double ball micrometer (ball diameter 6 mm) that can display up to 0.001 mm. Calculated by the following formula.
Vf = W2 / (ρ × T2) × 100 (%)
here,
W2: Mass per 1 m ^{2 of} reinforcing fiber base T2: Thickness (average value at 10 points)
ρ: Reinforcing fiber density (g / cm ³ )
It is.

  The present invention is applicable to any preform and FRP having a corner portion.

It is a schematic sectional drawing which shows a series of processes until shape | molding FRP using the manufacturing method of the preform which has a corner part which concerns on one embodiment of this invention, and the preform manufactured by the method. It is a schematic sectional drawing which shows a series of processes in the manufacturing method of FRP which has the conventional corner part. It is a schematic sectional drawing which shows a series of processes in the manufacturing method of FRP which has another conventional corner part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base tool 2 Male mold 3 as a shaping jig 4 Hot water piping 4 Resin diffusion medium 5 Peel ply 6 as release layer Adhesive material 7 Reinforced fiber base material 8 Rubber sheet 9 Sealing material 10 Preform 11 Thermal insulation cover 12 As mold Female mold 13 Bagging film 14 as bag material Sealing material 15 FRP

Claims (3)

A method of manufacturing a preform for FRP molding having a corner portion, which is formed using a reinforcing fiber base material, on a shaping jig having a corner portion corresponding to the corner portion of the preform. As described above, a resin diffusion medium for diffusing a resin during FRP molding and a release layer for peeling the resin diffusion medium from the FRP after molding are arranged in this order, and a reinforcing fiber base is formed on the auxiliary material. An adhesive material is interposed between them, and a rubber sheet is placed on the adhesive material to depressurize the inside to apply pressure by the rubber sheet, and the auxiliary material and the reinforcing fiber base are integrated with the adhesive material. turned into while, after the integrated material and along the shaping jig shaping, by demolding the preform after releasing pressurization by the rubber sheet, at least the preform code Over portion and over the both side portions, the production method of the preform, which comprises shaping a preform in a state of integrating the auxiliary materials to the reinforcing fiber base. A method for producing FRP, wherein the preform produced by the method according to claim 1 is placed on a mold, the entire preform is covered with a bag material, the inside is decompressed, and a resin is injected into the preform. . The preform manufactured by the method according to claim 1 is placed in a female mold having a shape obtained by inverting the shape of the shaping jig, the entire preform is covered with a bag material, and the inside is decompressed, A method for producing FRP, wherein a resin is injected into the preform.

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