JP2009101546A - Method for manufacturing fiber-reinforced plastic tubular body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fiber-reinforced plastic tubular body having high strength, uniform thickness and an excellent exterior appearance, while styrene is prevented from being diffused during manufacturing. <P>SOLUTION: The method for manufacturing the fiber-reinforced plastic tubular body is a vacuum injection molding method comprising the steps of: arranging a sheet-like reinforcing fibrous base material being an object to be impregnated on a cylindrical molding mold; laying a resin diffusing member for promoting the diffusion of a resin to be injected on the reinforcing fibrous base material while interposing a mold releasing agent between them; airtightly covering these reinforcing fibrous base material, mold releasing agent and resin diffusing member with a bagging film on the molding mold; and evacuating air in the bagging film and sucking/injecting the resin into the bagging film to impregnate the reinforcing fibrous base material with the injected resin. A laminate obtained by layering a fiber knitted/woven fabric, a granular material and a nonwoven fabric is used as the reinforcing fibrous base material. <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).

JP 2002-307463 A

  When forming a tube body using this vacuum injection molding method, a woven fabric is generally used for the reinforcing fiber base material to be impregnated, but in that case, the woven fabric is not evenly aligned, so it is uniform. It is difficult to wrap around a mold with high tension. Therefore, the tension when wrapping around the mold is weakened. As shown in Fig. 3, the fiber base is slack and has poor appearance such as irregularities such as wrinkles. There is a problem that it 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 present inventors have used two kinds of sheet-like materials, a granular material, a fiber knitted fabric, and a nonwoven fabric. By wrapping fiber knitted fabric and non-woven fabric with force, the granular material enters the fiber knitted fabric, and because it is wound with high tension, the layer of granular material is stuck and solidified during vacuum suction. As a result, the present inventors have found that it becomes difficult to sag and can prevent the occurrence of remarkable appearance irregularities, and based on this knowledge, the present invention has been made.

  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 airtightly covered on the mold by the bag film, and the inside of the bag film is in a vacuum reduced pressure state. A vacuum injection molding method for a fiber reinforced plastic tube in which a resin is sucked and injected into a bag film to impregnate the reinforced fiber base material with a resin, and a fiber knitted fabric, a granular material and a non-woven fabric are used as the reinforced fiber base material. A method for producing a fiber-reinforced plastic tubular body characterized by being used by being laminated is provided.

  According to a second aspect of the present invention, in the first aspect, the fiber knitted fabric is a reinforced fiber knitted fabric comprising a stitch fabric, a glass cloth, a carbon cloth, or a Kevlar cloth. A method of manufacturing a plastic tube is provided.

  According to a third aspect of the present invention, there is provided a method for producing a fiber-reinforced plastic tubular body according to the first or second aspect, wherein the granular material is silica sand or glass beads.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the granular material has an average particle diameter of 0.05 to 2 mm. A manufacturing method is provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth 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 sixth aspect of the present invention, there is provided the method for producing a fiber-reinforced plastic tubular body according to the fifth 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 granular materials, fiber knitted fabrics and nonwoven fabrics 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. Reinforcing fiber base material A fiber knitted fabric, a nonwoven fabric granular material, and a granular material are laminated | stacked and used for a reinforcing fiber base material.

<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 stitch fabric, glass cloth, carbon cloth, and Kevlar cloth are resin permeability. It is excellent in that the direction of the fiber base material can be freely changed, and the degree of freedom in strength design is great.

<Granular material>
The granular material is not particularly limited, but inorganic materials such as ceramics, metal, cermet, and other inorganic materials are generally used.
Examples of ceramics include oxides such as silica, alumina, magnesia, zirconia, titania, iron oxide and potassium titanate, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, phlogopite, Muscovite, zeolite, sericite, pyrophyllite, bentonite, alumina silicate, talc, clay, kaolin, silicate such as calcium silicate, hydroxide such as magnesium hydroxide, dredged sand, mica, glass, sialon, spinel mullite, Examples thereof include silicon nitride, boron nitride, silicon carbide, etc., and these may be used alone or in combination of two or more.
As the granular material, ceramic beads, ceramic molded bodies, for example, pulverized materials such as ceramics and porcelain, etc. are used, and in particular, silica sand is excellent in resin permeability, is inexpensive, and is obtained by curing with a thermosetting resin. The quality as a laminated product is also excellent, and glass beads may be used.
The average particle size of the granular material is preferably in the range of 0.05 to 2 mm. When the average particle size is less than 0.05 mm, the resin permeability is deteriorated. When the average particle size is more than 2 mm, the porosity is increased, the resin ratio is increased, and the cost is increased. It tends to occur. The average particle size is determined based on the particle size distribution measured according to a conventional method using a laser diffraction particle size distribution measuring machine.
The shape of the granular material is a cubic shape, a spindle shape, a columnar shape, a needle shape, a spherical shape, an indeterminate shape, etc., but preferably a spherical shape, a cubic shape, or a spindle shape.

<Nonwoven fabric>
Examples of the nonwoven fabric include glass fibers, polyester fibers, and vinylon fibers that are generally used for improving the appearance of fiber-reinforced plastics. As a fabric weight of a nonwoven fabric, 25-100 g / m < ² > is preferable.

  In the method of the present invention, as shown in FIG. 5, the fiber knitted fabric and the non-woven fabric are wound around a forming die while alternately applying tension, and are laminated while spraying the granular material on the fiber knitted fabric.

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.

3. Vacuum Injection Molding Method 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. 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 By a vacuum injection molding method as referred to in the schematic diagram of FIG. 1 described above, a fiber reinforced plastic tube having a diameter of 160 mmφ and a length of 300 mm was prepared using the following injection resin and various materials.
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 substrate 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 ) 4 sheets Nonwoven fabric: Spunbond 20307WTD (trade name, Unitika Co., Ltd., thickness 0.16 mm) 4 granular materials: silica sand No. 5 (general commercial product, particle size 0.3 to 0.6 mm) spraying amount 1,030 g / m ² 3 layers

Comparative Example A fiber-reinforced plastic tube having a diameter of 160 mmφ 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 base material.
The appearance evaluation results and thickness (unit: mm) measurement results of each example are shown in Table 1.

  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 fiber base material at the time of vacuum suction. The schematic diagram of an example of the fiber base material of an impregnation thing. The schematic diagram which shows the winding method of the to-be-impregnated thing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Reinforcing fiber base material 3 Release material 4 Resin diffusion member 5 Bag film 6 Seal material 7 Injection line 8 Vacuum decompression line

Claims (6)

  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 of vacuum injection molding of a fiber reinforced plastic tube body in which a fiber base material is impregnated with a resin, wherein the fiber base material is made of a fiber knitted fabric, a granular material and a non-woven fabric laminated as a reinforcing fiber base material. A method for manufacturing a tubular body.   The method for producing a fiber-reinforced plastic pipe according to claim 1, wherein the fiber knitted fabric is a reinforced fiber knitted fabric made of stitch fabric, glass cloth, carbon cloth, or Kevlar cloth.   The method for producing a fiber-reinforced plastic tubular body according to claim 1 or 2, wherein the granular material is silica sand or glass beads.   The method for producing a fiber-reinforced plastic tubular body according to any one of claims 1 to 3, wherein the granular material has an average particle diameter of 0.05 to 2 mm.   The method for producing a fiber-reinforced plastic pipe according to any one of claims 1 to 4, 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 5, wherein the injected resin has a viscosity of 0.2 Pa · s or less.

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