JP2009061655A - Method of manufacturing fiber-reinforced plastic pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a fiber-reinforced plastic pipe which has high strength and even thickness, and is superior in appearance while preventing styrene from being diffused during the manufacturing. <P>SOLUTION: The method of manufacturing fiber-reinforced plastic pipe being the vacuum injection molding method of the fiber-reinforced plastic pipe comprises: a process of disposing a sheet-like reinforcing fiber base material 2 as an object to be impregnated on a cylindrical molding mold; a process of laying a resin diffusion member 4 which prompts diffusion of injection resin via a release material 3 on the reinforcing fiber base material; a process of air-tightly covering the reinforcing fiber base material, release material and resin diffusion member with a bag film 5 over the molding mold; a process of sucking and injecting the resin into the bag film while evacuating the inside of the bag film to impregnate the reinforcing fiber base material with the resin, wherein the reinforcing fiber base material prepared by laminating a stitched fabric and an extensible sheet is used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a fiber reinforced plastic tube, and more particularly, a method for producing a fiber reinforced plastic tube having high strength, uniform wall thickness, and excellent appearance while preventing styrene diffusion during production. It is about.

Conventionally, fiber reinforced plastic (FRP) has been used in various industrial fields as a lightweight and high strength material.
In addition, it is well known that a filament winding (FW) method is used to manufacture a fiber reinforced plastic tube. However, since this molding method is wound around the molding die of the resin-impregnated fiber in an open state, there is an environmental problem such as volatilization of styrene during the production. As a molding method, a vacuum injection molding method in which molding is performed in a reduced pressure environment by vacuum suction is drawing attention.

  In the vacuum injection molding method, basically, a reinforcing fiber base is disposed on a mold, and a resin diffusion material is appropriately provided through a release material, which is covered with a bag film, sealed, and sealed with a bag film. This is a molding method in which a molded body is obtained by injecting resin into a bag film with the covered interior in a vacuum and reduced pressure state (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-307463

  When forming a tube body using this vacuum injection molding method, a knitted fabric is generally used for the reinforcing fiber base material to be impregnated, but in that case, the knitted fabric is not perfect for fiber alignment, It is difficult to wrap around a mold with a uniform high tension force, so the tension force when wrapping around the mold is weakened, and the knitted fabric sags, as shown in FIG. There is a problem that is likely to occur.

  Under such circumstances, the present invention aims to prevent diffusion of styrene during production, and to provide a method for producing a fiber-reinforced plastic tubular body having high strength, uniform wall thickness, and excellent appearance. To do.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention particularly made the reinforcing fiber base material by laminating two kinds of sheet-like materials each having a resin reinforcing ability and a stretchable function. By winding the stretchable sheet with high tension from the top of the fiber knitted fabric and increasing the tightening force by the restoring force of the stretchable sheet, the looseness of the fiber knitted fabric can be reduced. It has been found that it can be prevented from occurring, and the present invention has been made based on this finding.

  That is, according to the first aspect of the present invention, a sheet-like reinforcing fiber base material to be impregnated is disposed on a cylindrical mold, and a release material is disposed on the reinforcing fiber base material. A resin diffusion member that promotes the diffusion of the injected resin is laid, and the reinforcing fiber base material, the release material, and the resin diffusion member are air-tightly covered on the mold by the bag film, and the bag film is evacuated to a vacuum. A vacuum injection molding method for a fiber reinforced plastic tube in which a resin is sucked and injected into a bag film and the resin is impregnated into the reinforcing fiber base, and the fiber knitted fabric and the stretchable sheet are laminated as the reinforcing fiber base. And a method for producing a fiber-reinforced plastic tube, characterized by being used in the present invention.

  Further, according to the second invention of the present invention, in the first invention, the fiber knitted fabric has a long fiber in which the fiber direction is aligned in a direction of 90 ± 10 ° with respect to the tube axis and the fiber direction as the tube axis. On the other hand, there is provided a method for producing a fiber-reinforced plastic tube, which is a stitch fabric in which long fibers aligned in the direction of 0 to ± 45 ° are braided with stitch yarns.

  According to a third invention of the present invention, in the first or second invention, the fiber knitted fabric is a reinforced fiber fabric made of glass cloth, carbon cloth, or Kevlar cloth. A method of manufacturing a tubular body is provided.

  According to the fourth invention of the present invention, in any one of the first to third inventions, a stitch fabric in which the elastic sheets are braided with stitch yarns that are aligned in a direction oblique to each other. There is provided a method for producing a fiber-reinforced plastic tubular body characterized by being a continuous long-fiber tricot knitted fabric or a stretchable nonwoven fabric.

  Further, according to the fifth aspect of the present invention, in the fourth aspect, the stitch fabric is formed by stitching continuous continuous fibers that are aligned in the +40 to 60 ° and −40 to −60 ° directions on the upper and lower surfaces. There is provided a method for producing a fiber-reinforced plastic tube characterized by being braided.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the injection resin is a vinyl ester resin, an unsaturated polyester resin, or an epoxy resin. A method of manufacturing a tubular body is provided.

  According to a seventh aspect of the present invention, there is provided the method for producing a fiber-reinforced plastic tubular body according to the sixth aspect, wherein the injected resin has a viscosity of 0.2 Pa · s or less. The

  According to the production method of the present invention, the diffusion of styrene during production can be prevented, and the obtained fiber reinforced plastic tubular body has high strength, uniform thickness, small variation in thickness, and irregularities such as sagging and wrinkles. The outstanding effect that the outstanding external appearance with few can be ensured is show | played.

The production method of the present invention is a vacuum injection molding method for a fiber reinforced plastic tube, in which a fiber knitted fabric and a stretchable sheet are laminated and used as a reinforcing fiber base material.
Hereinafter, the manufacturing method of the present invention will be described in detail with respect to the reinforcing fiber substrate, the injection resin, the vacuum injection molding method and the like used therein.

1. Reinforced fiber base material A fiber knitted fabric and an elastic sheet are laminated and used for the reinforcing fiber base material. Preferably, as shown in FIG. 4, the fiber knitted fabric 21 and the elastic sheet 22 are alternately multiplexed. Used in stacked form.

<Fiber knitted fabric>
Examples of the fiber knitted fabric include a knitted fabric made of a fibrous material generally used as a base material, particularly a reinforced fiber knitted fabric, and in particular, a long fiber aligned in a direction of 90 ± 10 ° with respect to the tube axis. Stitch fabric, glass cloth, carbon cloth, and Kevlar cloth, which are made of braided yarn and stitched together with long fibers aligned in the direction of 0 to ± 45 ° with respect to the tube axis, are excellent in resin permeability. The direction of the substrate can be freely changed, and the degree of freedom in strength design is great.

<Elastic sheet>
Examples of the elastic sheet include a stitch fabric in which long fibers aligned in a direction oblique to each other are knitted with stitch yarns, a continuous long fiber knitted fabric, an elastic nonwoven fabric, and the like. Examples of the fabric include a stitch fabric that is aligned on +40 to 60 ° and −40 to −60 ° on two sides and then knitted with stitch yarn, and a tricot knitted fabric of continuous long fibers.
As an elastic sheet, the above-mentioned stitch fabric with the fiber direction aligned to +40 to 60 ° and −40 to −60 ° can contribute to strength design as a strength imparting member, and also to resin permeability. Is also preferable.

In the method of the present invention, the fiber knitted fabric and the stretchable sheet are preferably wound and laminated on a mold while alternately applying tension as shown in FIG.
In this way, the stretchable sheet was perpendicular to the orientation angle as shown in FIG. 6 before winding, but it became 90 ° or less by the tension as shown in FIG. When you loosen it, the restoring force will work to restore it.

2. Injection resin As the injection resin, a vinyl ester resin, an unsaturated polyester resin, an epoxy resin, or the like is preferable, and a resin having a viscosity of 0.2 Pa · s or less is preferable in consideration of impregnation properties.

  If necessary, the injection resin may be added with known additives such as an ultraviolet absorber, an ultraviolet degradation inhibitor, an oxidation degradation inhibitor, a pigment, and a flame retardant to improve durability such as weather resistance. May be.

In the method of the present invention, a desired fiber-reinforced plastic tube is obtained by the vacuum injection molding method using the above raw materials.
The vacuum injection molding method will be described with reference to the schematic diagram of FIG. 1. A predetermined reinforcing fiber base material is disposed in a laminated form on the cylindrical molding die 1 as will be described later. A resin diffusion member is laid through the release material, and these reinforcing fiber base material, release material, and resin diffusion member are airtightly covered on the mold with the bag film 5, and the bag film is evacuated to a vacuum pressure. A resin for injection is sucked and injected into the reinforcing fiber base to impregnate the resin.

That is, as apparent from FIG. 2 as a cross-sectional view taken along the line AA ′ of FIG. 1, the reinforcing fiber base material 2, the release material 3, and the resin diffusion member 4 are formed on the outer periphery of the cylindrical mold 1. They are arranged and laminated in this order, covered with a bag film 5, and sealed with a sealing material 6 so that the inside of the bag film becomes airtight.
As shown in FIG. 4, the reinforcing fiber base 2 is formed by laminating a fiber knitted fabric 21 and an elastic sheet 22, and is preferably wound while applying tension to a forming die.
The release material 3 enhances the release property of the resin, and a sheet made of an injection resin and a non-adhesive material is preferable.
The resin diffusing member 4 laid on the mold release material 3 promotes the diffusion of the injecting resin, impregnates the injecting resin into the reinforcing fiber base 2 evenly, and at the same time, a desired mold on the mold 1 A net-like sheet material capable of diffusing the injection resin over the entire range is preferable.
The bag film 5 covers the mold 1 in which these materials are laminated in an airtight manner, and is particularly an airtight synthetic resin film material generally used in this type of vacuum injection molding method. It is not limited.
The sealing material 6 is an adhesive material or the like, and the bag film 5 is fixed to the surface of the molding die 1 at both end portions of the molding die 1, thereby airtight and between the molding die 1 and the bag film 5. It is configured as a sealed molded part.
An injection line 7 for injecting an injecting resin into the bag film 5 is connected to the mold 1 covered with the bag film 5, and a vacuum depressurization source (Fig. (Not shown) and a vacuum decompression line 8 connected to the vacuum decompression source.
Then, an injection resin is injected into the molded part thus configured under a vacuum reduced pressure state by vacuum suction, so that a fiber-reinforced plastic tubular body having a desired shape is obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.

Example A tube made of fiber reinforced plastic having a diameter of 160φ and a length of 300 mm was prepared using the following injection resin and various materials by the vacuum injection molding method as referred to in the schematic diagram of FIG.
Resin for injection: Neopol 8250 (trade name, manufactured by Nippon Yupica Co., Ltd.)
Resin diffusion member: GREENFLOW 75 (trade name, manufactured by AIRTECH, polypropylene net of 0.88 mm thickness)
Mold release material: BLEEDER LEASE B (trade name, manufactured by AIRTECH, 0.011 mm thick silicone-coated polyamide sheet)
Reinforced fiber base material Reinforced fiber knitted fabric: Easy Fab WF800 (trade name, manufactured by FRP Service Co., Ltd., fiber orientation 0 °, 90 ° stitch fabric, mass 810 g / m ² ) 3 sheets Elastic sheet: Easy Fab DB 800 (Product Name, manufactured by FRP Service Co., Ltd., stitch fabric with fiber orientation ± 45 °, mass 777 g / m ² ) 3 sheets

Comparative Example A fiber-reinforced plastic tube having a diameter of 160φ and a length of 300 mm was prepared in the same manner as in the example except that only six reinforcing fiber knitted fabrics were used as the reinforcing fiber substrate.
Table 1 shows the appearance evaluation results and thickness measurement results of each example.
Evaluation results

Appearance evaluation ○ No wrinkles × Wrinkles

  From this, it can be seen that in the comparative example, wrinkles occur and the thickness varies, whereas in the example, no wrinkles occur and the thickness varies little.

  The method of the present invention makes it possible to produce a fiber-reinforced plastic pipe body that is free from wrinkles and has a small thickness variation, and is very useful in industry.

The schematic diagram of an example of the shaping | molding apparatus used for the manufacturing method of this invention. AA 'sectional drawing in the shaping | molding apparatus of FIG. The schematic diagram which shows the sagging state of the knitted fabric at the time of vacuum suction. The schematic diagram of an example of the reinforced fiber base material of an impregnation thing. The schematic diagram which shows the winding method of the to-be-impregnated thing. The schematic diagram of an example of the elastic sheet before winding. The schematic diagram of an example of the elastic sheet after winding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Reinforcement fiber base material 21 Textile knitted fabric 22 Elastic sheet 3 Release material 4 Resin diffusion member 5 Bag film 6 Seal material 7 Injection line 8 Vacuum decompression line

Claims (7)

  A sheet-like reinforcing fiber base material to be impregnated is disposed on a cylindrical mold, and a resin diffusion member that promotes the diffusion of the injected resin is laid on the reinforcing fiber base material through a release material. These reinforced fiber base material, mold release material and resin diffusion member are airtightly covered on the mold by the bag film, and the bag film is evacuated and vacuumed to inject and inject the resin into the bag film for reinforcement. A method for vacuum injection molding of a fiber reinforced plastic tube body in which a fiber base material is impregnated with a resin, wherein the fiber knitted fabric and a stretchable sheet are laminated and used as the reinforced fiber base material. Body manufacturing method.   The stitched yarn is a long fiber whose fiber direction is aligned in the 90 ± 10 ° direction with respect to the tube axis and a long fiber whose fiber direction is aligned in the direction of 0 to ± 45 ° with respect to the tube axis. 2. The method for producing a fiber-reinforced plastic pipe body according to claim 1, wherein the stitch fabric is a knitted stitch fabric.   The method for producing a fiber-reinforced plastic pipe according to claim 1 or 2, wherein the fiber knitted fabric is a reinforced fiber fabric made of glass cloth, carbon cloth, or Kevlar cloth.   The stretchable sheet is a stitch fabric obtained by braiding long fibers aligned in a direction oblique to each other with a stitch yarn, a tricot knitted fabric of continuous long fibers, or a stretchable nonwoven fabric, according to Claims 1 to 3. The manufacturing method of the fiber reinforced plastic pipe body in any one.   The fiber reinforcement according to claim 4, wherein the stitch fabric is formed by stitching continuous long fibers aligned in +40 to 60 ° and -40 to -60 ° directions on two upper and lower surfaces with stitch yarns. A method of manufacturing a plastic tube.   The method for producing a fiber-reinforced plastic pipe according to any one of claims 1 to 5, wherein the injected resin is a vinyl ester resin, an unsaturated polyester resin, or an epoxy resin.   The method for producing a fiber-reinforced plastic pipe body according to claim 6, wherein the injected resin has a viscosity of 0.2 Pa · s or less.

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