JP4769044B2 - Vacuum injection molding method for fiber reinforced resin molded products - Google Patents

Description

  The present invention relates to a vacuum injection molding method for fiber-reinforced resin molded products.

  As a lightweight and high-strength material, fiber reinforced plastic (FRP) is attracting attention in various industrial fields. Among them, carbon fiber reinforced plastic is being frequently used due to its excellent mechanical properties. Such fiber reinforced plastics are often formed by a conventional hand lay-up molding method. However, such fiber reinforced plastics are not preferable for manufacturing a relatively large molded product, and cost is high. In recent years, a vacuum injection molding method in which molding is performed in a reduced pressure environment by vacuum suction is being adopted.

The basic technique of this type of vacuum injection molding method is disclosed in, for example, Patent Document 1, in which a fiber layup layer is disposed in a mold and an injection tube for resin distribution is disposed thereon. The bag is covered with a bag film, the periphery thereof is sealed, and a resin is injected into the vacuum-sucked bag film to obtain a molded product.
JP-A-10-504001

  The conventional vacuum injection molding method as described above is a technique used for manufacturing a thin molded product among various molding methods, so when forming a thick molded product or a relatively large molded product. In the same method as described above, it is difficult to uniformly diffuse the injected resin.

  Further, in the case of a molded product having a corner portion having a substantially L-shaped or substantially U-shaped cross section, as well as a planar molded product, the flow direction and flow of the injected resin in the vicinity of the corner portion. The speed may change, and it may be difficult to uniformly diffuse the resin, resulting in poor impregnation.

  Therefore, the present invention has been made in view of the above circumstances, and is injected when a relatively large molded article, a thick molded article, or a molded article having a corner portion is manufactured. A fiber-reinforced resin molded product vacuum that enables the resin to be uniformly diffused and efficiently molded without causing poor impregnation, and to obtain a molded product that fully exhibits the strength and elasticity of reinforcing fibers. An injection molding method is provided.

In order to achieve the above-described object, the present invention forms a reinforcing fiber substrate layer by laminating a plurality of types of reinforcing fiber substrates on a mold, and the reinforcing fiber substrate layer is formed on the mold by a bag film. A molded part is formed by connecting a decompression line for decompressing the inside of the bag film and an injection line for injecting the resin into the bag film, and the resin is injected into the molded part in a decompressed environment by vacuum suction. A method for vacuum injection molding of a fiber reinforced resin molded article obtained, wherein the reinforcing fiber base layer is composed of a lower layer disposed in the vicinity of the surface of the mold and an upper layer on the lower layer. different, wherein the lower layer, a plurality of biaxial stitch base, by alternately laminating a sheet of glass chopped strand mat, many compounded than the upper layer biaxially stitch base, the biaxially Stitch The material is arranged in parallel so that warp yarns made of reinforcing fiber yarns are perpendicular to the weft yarns made of reinforcing fiber yarns and form continuous gaps, and these warp yarns and weft yarns are stitched together to form a recess on the surface. And the concave portion of the biaxial stitch base material is a groove for resin flow .

According to the present invention, the lower reinforcing fiber stitch base material has a continuous gap between the warp yarns, so that the surface of the base material has irregularities, and the injected resin flows through the concave portions. Therefore, the resin impregnated up to the surface of the mold is improved by the biaxial stitch base of the reinforcing fiber base constituting the lower layer, and the flow rate is not lowered or stays evenly. Diffuse and impregnate . Therefore, diffusivity and impregnation of the injection resin is heightened is, without causing the resin impregnation defects, it is possible to obtain a good molded article with stable quality.

In the molding method having the above-described configuration, the mold includes a guide path forming surface that forms an inner surface spiral guide path of a vertical sewer pipe and a hanging piece forming surface that is suspended from the outer peripheral edge of the guide path forming surface. It is a shape having a corner portion, and the upper layer of the reinforcing fiber base layer includes a glass roving cloth and a biaxial stitch base material, and is laminated by blending the glass roving cloth more than the biaxial stitch base material. and, Rukoto to mold the inner surface helical guideway is preferred.

With such a configuration, it is possible to avoid the resin flow direction from changing or staying in the vicinity of the corner formed by the guide path forming surface and the hanging piece forming surface of the mold, and impregnation failure. It is possible to form a spiral guide path in a good state without causing any problems .

  According to the vacuum injection molding method of the fiber-reinforced resin molded article of the present invention configured as described above, a relatively large molded article, a thick molded article, or a molded article having a corner portion is manufactured. In this case, it is possible to efficiently mold the resin without causing impregnation failure by uniformly diffusing the injected resin. Therefore, it is possible to provide a molded product with a stable quality that sufficiently exhibits the strength and elasticity of the reinforcing fiber.

  In addition, by using the stitch base as described above, the flow rate of the injected resin can be increased, thereby shortening the molding time.

  Hereinafter, the best mode for carrying out the vacuum injection molding method for a fiber-reinforced resin molded article according to the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a vacuum injection molding method for a fiber-reinforced resin molded article of the present invention.

  In the mold 1, a plurality of types of reinforcing fiber substrates are laminated to form the reinforcing fiber substrate layer 2. In this reinforcing fiber base layer 2, at least the lower layer 21 disposed in the vicinity of the surface of the mold 1 and the upper layer 22 disposed on the outer side thereof have different configurations of the reinforcing fiber base to be laminated. It is configured. The reinforcing fiber substrate is preferably a substrate made of inorganic fibers such as glass fibers and carbon fibers.

  In the present invention, the lower layer 21 contains more reinforcing fiber stitch base material than the upper layer. This reinforcing fiber stitch base material is a fiber base material having a structure in which warp yarns are arranged parallel to the weft yarns so as to have a continuous gap and are stitched together by stitch yarns such as glass fibers or polyester fibers.

  A release sheet 3 is laid on the reinforcing fiber base layer 2. The release sheet 3 enhances the release property of the cured injection resin, and a sheet made of an injection resin and a non-adhesive material is preferable.

  Next, the resin diffusion net 4 is laid on the release sheet 3. The resin diffusion net 4 promotes the diffusion of the injected resin. The resin diffusion net 4 impregnates the injected resin into the reinforcing fiber material 2 evenly and can diffuse the injected resin over the entire desired range on the mold 1. A sheet material is preferred.

  Subsequently, the mold 1 in which these base materials are laminated is air-tightly covered with the bag film 5. The bag film 5 is not particularly limited as long as it is an airtight synthetic resin film material generally used in this type of vacuum injection molding method. Then, the bag film 5 is fixed to the surface of the mold 1 using a sealing material 7 such as an adhesive material at the periphery of the mold 1. Thereby, between the shaping | molding die 1 and the bag film 5 is comprised as an airtight and sealed shaping | molding part.

  The mold 1 covered with the bag film 5 is connected to a decompression source 8 that sucks and decompresses air in the molding part and a decompression line 81 connected to the decompression source 8. Further, an injection line 9 for injecting resin into the bag film 5 is connected.

  And resin is inject | poured in the pressure_reduction | reduced_pressure environment by vacuum suction in the shaping | molding part comprised in this way, and the fiber reinforced resin molded product of a desired shape is obtained.

  FIG. 2 shows Example 1 of the vacuum injection molding method for a fiber-reinforced resin molded article of the present invention, and is an explanatory view schematically showing a molding part viewed from the cross-sectional direction.

  In the vacuum injection molding method of the present embodiment, an inner surface spiral guide path used for a natural downflow vertical sewer pipe or the like is formed, and a spiral upper surface guide path installed in the vertical pipe, and a guide It is a guide path having a shape provided with a curved joining piece that stands on the outer peripheral edge of the road and can be joined to the inner peripheral surface of the vertical pipe.

  The illustrated mold 1 is formed in a substantially L-shaped cross section and has a corner portion. The molding die 1 has a shape including a guide path forming surface 11 through the corner portion and a hanging piece forming surface 12 suspended from the outer peripheral edge of the guide path forming surface 11. The material of the mold 1 used here may be any material such as fiber reinforced resin, synthetic resin, metal, and the like, and is appropriately selected according to the fluidity and demolding property of the injected resin.

  The spiral guide path is formed by first forming a reinforcing fiber base layer on the mold 1. The reinforcing fiber base layer 2 has a two-layer configuration of a lower layer 21 disposed in the vicinity of the surface of the mold 1 and an upper layer 22 disposed on the outer side thereof.

  Among these, a plurality of biaxial stitch base materials 211 and a single glass chopped strand mat 212 are alternately laminated on the lower layer 21 of the reinforcing fiber base layer 2.

  The biaxial stitch base material 211 has a structure in which warp yarns and weft yarns are orthogonally arranged so that reinforcing fiber bundles including glass rovings are overlapped in two directions, and a predetermined gap is provided between the warp yarns and integrated with stitching, This is a fiber base material having a structure in which irregularities are formed on the surface and the concave portions can serve as grooves for resin flow. For example, four of them are laminated, and a glass chop strand mat 212 is laminated thereon to constitute the lower layer 21.

  The glass chop strand mat 212 is formed by cutting glass strands obtained by focusing glass fiber filaments into a predetermined length and orienting them in the plane.

  The reinforcing fiber base layer 2 is formed by laminating, for example, a glass roving cloth, a biaxial stitch base material, and a glass chop strand mat in the upper layer 22 disposed outside the mold 1. The glass roving cloth is a fiber base material formed into a woven fabric using a roving formed by aligning glass strands obtained by bundling glass fiber filaments as a weft.

  The mixing ratio of the glass roving cloth and the biaxial stitch base material is, for example, a ratio of 3: 1. A glass chop strand mat is laminated on the glass roving cloth and the biaxial stitch base material arranged at this ratio. Configured.

  On the reinforcing fiber base layer 2 thus configured, a release sheet 3 and a resin diffusion net 4 are laid and covered airtight with a bag film 5. Further, a decompression line and a resin injection line are connected in the bag film 5, and the bag film 5 is decompressed to inject the resin in a vacuum environment.

  As the injection resin, for example, a low-viscosity vinyl ester resin, an unsaturated polyester resin, an epoxy resin, and the like are preferable. The viscosity of the injected resin is preferably 0.2 Pa · s (= 2 Poise) or less in consideration of the resin impregnation property. The injected resin is uniformly diffused throughout the molded portion through the resin diffusion net 4 and impregnated in the reinforcing fiber base layer 2.

  Since the illustrated biaxial stitch base material 211 has a large reinforcing effect and a high fiber density, it can ensure a sufficient strength for a molded product and has high resin fluidity on the surface of the base material. Therefore, when the injected resin reaches the lower layer 21, it flows and uniformly diffuses on the surface of the base material and impregnates the base material without reducing the flow rate.

  Thereby, in the vicinity of the corner portion between the guide path forming surface 11 and the hanging piece forming surface 12 of the mold 1, it is possible to avoid the resin flow direction from changing or the resin from staying in the corner portion. It is possible to form a spiral guide path in a good state without causing any problems.

  Moreover, in the vacuum injection molding method of the fiber reinforced resin molded product of the present invention, the laminated form of the lower layer 21 and the upper layer 22 of the reinforcing fiber base layer 2 is not limited to the above configuration. Any laminated structure may be used as long as the composition improves the fluidity of the resin, for example, the mixing ratio with the biaxial stitch substrate is 4: 1.

  The present invention can be applied to molding a relatively large and thick fiber reinforced resin molded article, for example, to produce an inner surface spiral guideway used for a natural downflow vertical sewer pipe or the like. It can be suitably used.

It is sectional drawing which shows typically the vacuum injection molding method of the fiber reinforced resin molded product which concerns on this invention. It is explanatory drawing which shows the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Reinforcement fiber base material layer 21 Lower layer 211 Biaxial stitch base material 212 Glass chop strand mat 22 Upper layer 3 Release sheet 4 Resin diffusion net 5 Bag film

Claims (2)

A reinforcing fiber substrate layer is formed by laminating a plurality of types of reinforcing fiber substrates on a mold, and the reinforcing fiber substrate layer is airtightly covered on the mold with a bag film and the inside of the bag film is decompressed. Vacuum injection molding method for a fiber reinforced resin molded product obtained by connecting a decompression line and an injection line for injecting resin into a bag film to form a molded part, and injecting the resin into the molded part in a reduced pressure environment by vacuum suction Because
The reinforcing fiber base layer is different in the configuration of the reinforcing fiber base to be laminated between the lower layer disposed in the vicinity of the surface of the mold and the upper layer on the lower layer ,
In the lower layer, a plurality of biaxial stitch base materials and a single glass chopped strand mat are alternately laminated, and the biaxial stitch base material is blended more than the upper layer ,
The biaxial stitch base material is arranged in parallel so that warp yarns made of reinforcing fiber yarns are perpendicular to the weft yarns made of reinforcing fiber yarns and form continuous gaps, and these warp yarns and weft yarns are integrated by stitching. And has a recess on the surface,
A vacuum injection molding method for a fiber-reinforced resin molded product, wherein the concave portion of the biaxial stitch base material is a groove for resin flow . In the vacuum injection molding method of the fiber reinforced resin molded product according to claim 1,
The mold has a corner portion having a guide path forming surface that forms an inner surface spiral guide path of a vertical sewer pipe and a hanging piece forming surface that is suspended from the outer peripheral edge of the guide path forming surface. ,
The upper layer of the reinforcing fiber base layer includes a glass roving cloth and a biaxial stitch base material. The glass roving cloth is mixed and laminated more than the biaxial stitch base material to form the inner spiral guide path. vacuum injection molding method of fiber reinforced resin molded article according to claim be Rukoto.

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