JP2008273010A - Method for manufacturing fiber-reinforced plastic molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fiber-reinforced plastic molded body utilizing a structural article for facilitating resin flow and resin feed as a reinforcing material without requiring discarding of the structural article, for example, a sheet-like or mat-like structural article. <P>SOLUTION: The method for manufacturing the fiber-reinforced plastic molded body comprises the steps of arranging an article 2 to be impregnated comprising a sheet-like reinforcing fiber material on a base stand 1 of a mold for molding, laying down a resin spreading member 3 for spreading and flowing a liquid matrix resin 11 on the article to be impregnated, covering hermetically these article to be impregnated and resin spreading member on the mold for molding with a bag film 5, and pouring the liquid matrix resin into the bag film under vacuum. In this method, the resin spreading member consists of the reinforcing fiber material bound with a compatible resin having compatibility with the liquid matrix resin, and the shape is held for a definite time, and after the resin spreading member is sucked and integrated on the article to be impregnated during this time, the compatible resin becomes compatible with the matrix resin with time and is absorbed into the matrix resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improved method for producing a fiber-reinforced plastic molded body.

As a lightweight and high-strength material, fiber reinforced plastic (FRP) has attracted attention in various industrial fields, and among them, carbon fiber reinforced plastic is being frequently used due to its excellent mechanical properties and the like. Such fiber reinforced plastics are often molded by a conventional hand-up molding method.
However, this molding method is not preferable for producing a relatively large and thick molded article, and is too costly, and styrene and the like are volatilized during the production. Therefore, in recent years, a vacuum injection molding method in which a resin is injected into a base material having a void made of a reinforcing fiber material under vacuum, for example, vacuum by vacuum suction, is being adopted as a basic technique. The material to be impregnated is placed on the mold, and further, a resin fluidized layer is provided through a release material, and a bag film covering the resin film is installed so that the periphery thereof can be sealed and vacuumed, A method for injecting and molding a resin into the bag film has been proposed (see, for example, Patent Document 1).

  In this molding method, the resin fluidized bed has a sheet-like or matte-like structure having a space in which the resin flows, such as polypropylene, so that the resin flows easily and the reinforcing fiber material to be impregnated can be replenished. A net-like structure such as a net is used. The release material is a sheet-like material that is interposed between the material to be impregnated and the resin fluidized layer to allow the resin to pass therethrough and to separate the two after the impregnation. The release material is predetermined on a nylon release cloth or a Teflon (registered trademark) film. The thing which made many holes at intervals is used. These sheet-like or mat-like structures and release materials cannot be reused and are disposable and have to be discarded every time they are molded. Further, the surface formed by separating the release cloth is conspicuous, and is inferior in smoothness. When reinforcing fiber material is used as the resin diffusion net to integrate with the reinforcing fiber material to be impregnated, after the resin is cured, only the resin is scattered in the space provided to ensure fluidity. This causes a problem that cracks occur in the resin portion after long-term use.

JP-A-60-83826

  Under such circumstances, the object of the present invention is to solve the problems of the conventional vacuum injection molding method and to use a resin flow structure used for easy flow and replenishment of resin, such as a sheet or mat. It is an object of the present invention to provide a method for producing a fiber-reinforced plastic molded body that can use a structure as a reinforcing material without requiring disposal of the structure.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors laid a resin diffusion member capable of diffusing and flowing a liquid matrix resin on an object to be impregnated made of a sheet-like reinforcing fiber material. It is possible to solve the problem by forming the article and the resin diffusing member in a structure in which the bag base is hermetically covered with the bag film and injecting the resin into the bag film of such a thing under vacuum. Based on this finding, the inventors have made the present invention.

  That is, according to the first aspect of the present invention, the resin diffusion that allows the impregnated material made of sheet-like reinforcing fiber material to be disposed on the mold base and allows the liquid matrix resin to diffuse and flow on the impregnated material. Laying the members, these impregnated materials and resin diffusion members are airtightly covered on the mold base by the bag film, and liquid matrix resin is injected into the bag film under vacuum, and the resin is solidified and molded. A method for producing a fiber reinforced plastic molded body, wherein the resin diffusion member is made of a reinforced fiber material bonded with a compatible resin compatible with the liquid matrix resin, and the shape is maintained for a certain period of time. Fiber reinforcement, characterized by being compatible with the matrix resin over time and absorbed by the matrix resin after being vacuumed and integrated on the material to be impregnated under vacuum Method for producing a plastic molded body is provided.

  According to a second aspect of the present invention, there is provided the method for producing a fiber-reinforced plastic molded body according to the first aspect, wherein the liquid matrix resin is made of a thermosetting resin.

  According to a third aspect of the present invention, there is provided the method for producing a fiber-reinforced plastic molded body according to the second aspect, wherein the thermosetting resin is an unsaturated polyester resin or a vinyl ester resin. The

  According to the fourth invention of the present invention, in any one of the first to third inventions, the resin diffusion member is a mat formed by bonding short fibers bonded with a compatible resin with the same resin. A method for producing a fiber-reinforced plastic molded product is provided.

  According to the fifth invention of the present invention, in any one of the first to third inventions, the resin diffusion member is a sheet formed by bonding long fibers bonded with a compatible resin with the same resin. A method for producing a fiber-reinforced plastic molded product is provided.

  According to a sixth invention of the present invention, in any one of the first to fifth inventions, the resin diffusion member has a network structure, and a method for producing a fiber-reinforced plastic molded body Is provided.

  According to a seventh aspect of the present invention, there is provided the method for producing a fiber-reinforced plastic molded body according to any one of the first to sixth aspects, further comprising laying a nonwoven fabric on the resin diffusion member. Provided.

  According to the manufacturing method of the present invention, the problems of the conventional vacuum injection molding method are solved, and a resin flow structure used for easily flowing and replenishing the resin, such as a sheet-like or mat-like structure, etc. Therefore, a remarkable effect is achieved such that the structure can be used as a reinforcing material.

  In the method of the present invention, a resin diffusion member for diffusing and flowing a liquid matrix resin is laid on an object to be impregnated disposed on a mold base, and the object base and the resin diffusion member are molded with a bag film. A method in which an air-tight coating is prepared, a liquid matrix resin is injected into the bag film under vacuum, and the resin is solidified and molded. The resin diffusion member is compatible with the injection resin. The material is made of a reinforced fiber material bonded with a compatible resin, and the shape is maintained for a certain period of time, and after being integrated with suction onto the material to be impregnated under vacuum, the compatible resin is used as a matrix resin over time. It is characterized by being dissolved and absorbed in a matrix resin.

  As the impregnated material used in the method of the present invention, fiber products made of reinforcing fibers generally used as a base material, especially fabrics, woven fabrics, nonwoven fabrics, such as woven fabrics such as glass cloth, carbon cloth, Kevlar cloth, and chopped Nonwoven fabrics such as strand mats can be mentioned.

Further, as the material for the resin diffusing member, reinforced fibers generally used for fiber reinforced resin molded products, among which glass fiber, carbon fiber, aramid fiber, etc. are easily available, and are preferably used. The shape is preferably a cross-sectional shape that facilitates securing a space where the resin flows when the fibers are stacked, for example, a circle, an ellipse, or a circle with irregularities on the surface. The reinforcing fiber in the resin diffusion member is compatible with the matrix resin. It is combined with a compatible compatible resin.
As described above, since the above-mentioned compatible resin is used as a binder to bond and fix the reinforcing fibers, in the molding method of the present invention, the shape of the resin diffusion member is maintained for a certain period of time, and the object to be impregnated under vacuum After the suction integration, the compatible resin is dissolved with the matrix resin over time and absorbed by the matrix resin, and the resin diffusion member is impregnated with the matrix resin together with the impregnated material, and the integrated molded body is formed. Will be formed.
The reinforcing fiber may be a short fiber or a long fiber. In the case of a short fiber, if it is too thin or too short, it is difficult to secure a space for the resin to flow, and it is too thick or too long. Since it is difficult to ensure the uniformity of the layer, the fiber diameter is generally 0.2 to 1.5 mm and the length is 5 to 50 mm, preferably the fiber diameter is 0.3 to 1 mm and the length is 10 to 30 mm. Well, in the case of long fibers, if the fiber diameter is too thin, the spread of the fibers when the resin is dissolved becomes small, so it is necessary to reduce the fiber spacing of the fabric, making it difficult to secure a space for the resin to flow, Even if it is too thick, the fiber crossing of the woven fabric is raised, and unevenness becomes conspicuous in the appearance of the product after solidification, so the fiber diameter is usually in the range of 0.2 to 1.5 mm, preferably 0.3 mm to 1 mm. It is good to do.
The shape of the reinforcing fiber is preferably a cross-sectional shape that facilitates securing a space in which the resin flows when the fibers are stacked, for example, a circle, an ellipse, or a circle with irregularities on the surface.
Examples of the resin diffusing member using short fibers include a sheet in which short fibers are hardened in a mat shape using the above compatible resin as a binder.
Examples of the resin diffusing member using long fibers include woven fabrics in which long fibers are cross-bonded and bonded using the above compatible resin as a binder, and the woven fabric is used in order to increase the space through which the resin flows and increase the impregnation speed. Multiple sheets may be used. Examples of the shape of the woven fabric include a square and rhombus biaxial assembly fabric, a triaxial assembly fabric, and a 4-axis assembly fabric.
As the bonding and fixing state with the compatible resin, the resin may enter and disperse into the fiber, or may be coated around the fiber.
The dose of the compatible resin can be appropriately set according to the impregnation time and the solidification time of the matrix resin injected in the vacuum injection molding.

  As this compatible resin, a resin that is easily dissolved in styrene contained in the matrix resin is preferable. For example, an unsaturated polyester resin, vinyl acetate, ethylene vinyl acetate copolymer, or the like is used. Among them, the unsaturated polyester resin is solidified by the same curing mechanism as the unsaturated polyester resin or vinyl ester resin of the matrix resin, and is preferable in terms of quality. Vinyl acetates are well known as glass fiber binders and the like, and are also suitably used in the method of the present invention.

  Examples of the matrix resin used in the method of the present invention include unsaturated polyester resins and vinyl ester resins containing styrene.

The nonwoven fabric used in the method of the present invention is laid on the resin diffusion member in order to improve the smoothness of the surface of the molded body. 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.

  The bag film is made of a material that is difficult to dissolve in styrene, such as polyethylene, polypropylene, polyethylene terephthalate, and polyamide. In particular, a film made of polyamide is often used from the viewpoint of performance and price.

  The vacuum injection molding according to the method of the present invention will be described with reference to the drawings. FIG. 1 shows a state before the matrix resin is injected, and FIG. 2 shows a state after the matrix resin is injected. In these drawings, 1 is a mold base and 2 is placed on the mold base. An impregnated material, 3 is a resin diffusing member, 4 is a nonwoven fabric that is appropriately used as necessary, 5 is a bag film installed so as to cover them, and 6 is interposed between the bag film 5 and the mold base 1. Vacuum holding sealing materials 7 and 8 are vacuum valves attached to both ends of the bag film 5, 9 is a resin reservoir tank connected to the vacuum valve 7 via the valve 10, 11 is a matrix resin for impregnation, 12 Is a drain connected to the vacuum valve 8 via a valve 13, and 14 is a vacuum system line connected to this drain via a valve 15.

An article to be impregnated 2 is placed on the mold base 1, and a resin diffusion member 3 is disposed adjacent thereto, and a nonwoven fabric 4 is laid thereon as necessary.
In this state, the bag film 5 is covered from above, and the sealing material 6 is disposed between the lower base and the mold base 1 and vacuum-sealed.
When the vacuum valves 7 and 8 are set on the bag film 5 and the valves 13 and 15 are opened, the air in the bag film 5 is discharged to the evacuation system line 14 via the drain 12, and the bag film 5 is in a vacuum state. Maintained.
When the valve 10 is opened in this state, as shown in FIG. 2, the matrix resin 11 for impregnation of the resin storage tank 9 is supplied into the bag film 5 through the vacuum valve 7 (when the nonwoven fabric 4 is used). Is filled in the resin diffusion member 3 in a flowable state, and is supplied to the material 2 to be impregnated and impregnated.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

Example 1
A steel plate having a size of 800 mm width × 1300 mm length is used for the mold base, and as an impregnated material to be placed thereon, roving cloth WR800C [(trade name, manufactured by Nittobo Co., Ltd., count: 800 (g / m ² )] 2 layers and chop strand mat MC900A [trade name, manufactured by Nittobo Co., Ltd., count: 900 (g / m ² )] 3 layers are alternately stacked with a width of 300 mm and a length of 500 mm. As a resin diffusing member, glass roving ERS290-554A (trade name, manufactured by Central Glass Fiber Co., Ltd., count: 290 g / 1000 m), Chemitylene PEB-13ST (trade name, manufactured by Sanyo Chemical Industries, Ltd., glass short fiber 7 by mass ratio) 3) as a binder, bonded and fixed to a short fiber (shape: circular, fiber diameter: 0.5 mm, length 10 mm), Secured to the laminated amount 400 g / m ² in sum polyester resin, formed by laminating, using a mounting mat such as shown in FIG. 3, NEOPOL 8250 (trade name, Nippon U-PICA Co., Ltd.) was used as the matrix resin, FIG. 1 Based on No. 2, vacuum injection molding was performed as described above without using the nonwoven fabric 4.

Example 2
Resin diffusion member is glass roving ERS290-554A (trade name, manufactured by Central Glass Fiber Co., Ltd., count: ^two fibers of 290 g / m ² are combined), Chemitylene PEB-13ST (trade name, manufactured by Sanyo Chemical Industries) Is bonded, fixed and woven as a binder, except that it is changed to a woven fabric (fiber shape: circular, fiber diameter: 0.8 mm, fiber interval: 1.5 mm, woven shape: square) as shown in FIG. Vacuum injection molding was performed in the same manner as in Example 1.

Example 3
Furthermore, vacuum injection molding was performed in the same manner as in Example 2 except that spunbond 10606WTD (trade name, manufactured by Unitika Ltd., nonwoven fabric with a thickness of 0.26 mm) was used as the nonwoven fabric 4.

Comparative Example 1
Vacuum injection molding was performed in the same manner as in Example 1 except that the resin diffusion member was not used.

Comparative Example 2
GREENFLOW 75 (trade name, manufactured by AIRTECH, 0.89 mm thick polypropylene net), which is a commercially available resin diffusion sheet, and BLEEDER LEASE B (trade name, manufactured by AIRTECH, 0.011 mm thick silicone) which is a commercially available release cloth Vacuum injection molding was performed in the same manner as in Example 3 except that the coated polyamide cloth) was used.

About the Example and the comparative example, the resin fluidity at the time of shaping | molding and the external appearance of the molded object were evaluated.
The resin fluidity was evaluated by a test method as shown in FIG.
That is, a predetermined impregnated material, a resin diffusion member, and a polyamide bag film are set on a flat mold base, and then a matrix resin is injected using a vacuum pump, and a resin flow distance is measured at regular intervals. And evaluated according to the following criteria.
○: Flow distance after 3 minutes 300 mm or more x: Flow distance after 3 minutes 100 mm or less The appearance was evaluated according to the following criteria.
◎: Surface smoothness, uniform color tone ○: Surface smoothness ×: Surface irregularity (texture)

  The evaluation results are shown in Table 1.

In each Example, the resin fluidity is improved as compared with Comparative Example 1 in which no resin diffusion member is used.
Moreover, compared with the comparative example 2 using a commercially available resin diffusion member, the fluidity | liquidity which does not have a practical problem is obtained although it is a little inferior, and since the release cloth is not used, it is smooth compared with the comparative example 2. Appearance was obtained.
When the nonwoven fabric was used, the smoothness of the appearance was further improved, and a molded product having a uniform color tone was obtained.

  The method of the present invention does not require the disposal of a resin flow structure, such as a sheet-like or mat-like structure, which is required in the conventional vacuum injection molding method, which contributes to environmental conservation and is industrially suitable. Is.

The schematic diagram before injection | pouring of matrix resin of an example of the shaping | molding apparatus used for the manufacturing method of this invention. The schematic diagram after the matrix resin injection | pouring of an example of the shaping | molding apparatus used for the manufacturing method of this invention. FIG. 3 is a schematic diagram of an example of a laminated mat as a resin diffusion member of Example 1. The schematic diagram of an example of the textile fabric as a resin diffusion member of Example 2. FIG. Explanatory drawing about the test method of evaluation of resin fluidity | liquidity. The graph which shows the test result of resin fluidity | liquidity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold base 2 Impregnated material 3 Resin diffusion member 4 Nonwoven fabric 5 Bag film 6 Seal material 7,8 Vacuum valve 9 Resin storage tank 10,13,15 Valve 11 Matrix resin 12 Drain 14 Vacuum drawing system line

Claims (7)

  An impregnated material made of sheet-like reinforcing fiber material is disposed on the mold base, and a resin diffusion member capable of diffusing and flowing the liquid matrix resin is laid on the impregnated material, and the impregnated material and the resin diffusion material are laid. A method for producing a fiber-reinforced plastic molded body in which a member is airtightly coated on a mold base with a bag film, a liquid matrix resin is injected into the bag film under vacuum, and the resin is solidified and molded. The resin diffusing member is made of a reinforced fiber material bonded with a compatible resin compatible with the liquid matrix resin, and the shape is maintained for a certain period of time, while being sucked and integrated on the material to be impregnated under vacuum. Thereafter, a method for producing a fiber-reinforced plastic molded article, wherein the compatible resin is dissolved with the matrix resin over time and absorbed by the matrix resin.   2. The method according to claim 1, wherein the liquid matrix resin comprises a thermosetting resin.   The method according to claim 2, wherein the thermosetting resin is an unsaturated polyester resin or a vinyl ester resin.   The manufacturing method according to any one of claims 1 to 3, wherein the resin diffusing member is a mat formed by bonding short fibers bonded with a compatible resin with the same resin.   The manufacturing method according to any one of claims 1 to 3, wherein the resin diffusion member is a sheet formed by bonding long fibers bonded with a compatible resin with the same resin.   The manufacturing method according to claim 1, wherein the resin diffusion member has a network structure.   Furthermore, a nonwoven fabric is laid on a resin diffusion member, The manufacturing method in any one of Claims 1-6 characterized by the above-mentioned.

Images