JP4160771B2 - Fiber reinforced plastic molded body molding apparatus and molding method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a fiber reinforced plastic (FRP) molding apparatus and a molding method thereof. Specifically, a sheet-like reinforcing fiber material arranged in a mold is hermetically encapsulated with a bag film, The present invention relates to a vacuum injection molding apparatus and a molding method for fiber reinforced plastics, in which a matrix resin is injected into a reinforced fiber material while reducing pressure.
[0002]
[Prior art]
The FRP molded body is molded by various methods such as spray-up method, RTM method, press molding, etc., but in the case of a large molded body, it is often molded by the hand lay-up method. This hand lay-up method is a molding method that has been performed for a relatively long time, but because the state of impregnation of the matrix resin to the reinforcing fiber material is managed manually, it is difficult to secure the personnel, There were problems such as inconvenience to the neighborhood due to odors that dissipated during work.
[0003]
Therefore, a method of arranging a reinforcing fiber material in a sealed mold and injecting a matrix resin under a vacuum pressure has been considered, but there has been a problem that the resin cannot be impregnated well. In order to improve this, for example, in Japanese Patent Laid-Open No. 2000-43172, a resin mesh is arranged on both the front and back surfaces of a core material made of foam, and a reinforcing fiber material is arranged on the surface of each mesh. Then, after encapsulating the whole with a bag film, the interior encapsulated with the bag film is in a vacuum state, and a matrix resin is injected through a plurality of grooves formed on the surface of the core material. A method of impregnating and integrating a resin into a reinforcing fiber material by diffusing in the surface direction of the reinforcing fiber material through a mesh is proposed.
[0004]
[Problems to be solved by the invention]
However, in the FRP molding method disclosed in the above publication, in order for the matrix resin to uniformly impregnate the entire reinforcing fiber material, it is necessary to reduce the pitch of grooves formed on the surface of the core material. If the groove processing is complicated, or the matrix resin that has been drawn in a vacuum and passed through the network is filled in the middle of impregnating the reinforcing fiber material, the suction force by the vacuum is evenly distributed on the surface side of the reinforcing fiber material. However, if the resin impregnation amount is not uniformly impregnated on the surface side of the reinforcing fiber material, or if the suction force by the vacuum exceeds the injection pressure of the resin, there arises a problem that it becomes difficult to maintain the shape of the reinforcing fiber material.
[0005]
The present invention has been developed to solve such a problem. Even if the specific object is a FRP molding apparatus and molding method by vacuum suction, the impregnation of the resin is evenly distributed over the entire reinforcing fiber material. Another object of the present invention is to provide an FRP molding apparatus and a molding method thereof that can achieve a stable shape.
[0006]
[Means for solving the problems and effects]
As a result of various investigations on the vacuum injection molding method of FRP in order to solve the above problems, the inventors have invented a method with good resin impregnation and good productivity.
[0007]
That is, the basic configuration of the molding apparatus according to the present invention includes a bag film in which a sheet-like reinforcing fiber material is disposed in a molding space of a mold, and a vacuum source that depressurizes the bag film. A vacuum injection molding apparatus for fiber reinforced plastic having an injection port for injecting a matrix resin into the fiber material, wherein one side of the molding space is opened, and the open side surface and periphery of the fiber material are sealed in a mold A porous film having a large number of small holes is disposed between the fixed bag film, and a degassing sheet having a degassing circuit is disposed between the porous film and the bag film. wherein said vacuum source is connected to the closed space between the deaerating sheet, to become arranged that the resin injection port toward the bottom of the opposite side of the porous film of the fiber material In the molding apparatus of a fiber reinforced plastic molding according to symptoms. With this configuration, resin impregnation is good and high productivity is achieved.
[0008]
The material of the mold used here may be any of metal, fiber reinforced resin, resin, and wood, and may be appropriately selected depending on the curing temperature of the matrix resin to be used. The mold shape is determined by the shape of the molded body. For molding, the entire surface of one side of the sheet-like reinforcing fiber material is encapsulated with a bag film. The sheet-like reinforcing fiber material does not need to be a single layer and may be laminated in multiple layers, and the fiber materials to be laminated may not be the same material. It is also possible to interpose a core material having a desired shape inside the sheet-like fiber material. Various synthetic resins can be used as the core material, and when further weight reduction is required, a foam is preferable. In addition to the core material, for example, metal mechanical parts may be attached to or interposed in the reinforcing fiber material.
[0009]
The bag film used at this time is not limited as long as it is an airtight synthetic resin film generally used in this type of vacuum injection molding method. The bag film is hermetically fixed to the mold with a sealing tape or an adhesive material so that the reduced pressure in the molding space is maintained. The porous film is preferably provided with a release property by arranging a fluororesin or the like on the inner surface thereof, but the material is not particularly limited as long as the material is a matrix resin and a non-adhesive material.
[0010]
The opening area of the holes formed in the porous film is ² to 1000 mm ² / m ² , and below this, the effect of vacuum suction cannot be obtained. Less effective. In addition, the number of apertures in the hole is desirably 100 or less per 1 m ² within the above-mentioned range. When the number is 100 or more, the degassing sheet is blocked as the resin is sucked up, and good impregnation characteristics are obtained. Cannot be obtained.
[0011]
The degassing sheet for the degassing circuit is provided with a suction port connected to a pressure reducing source such as a vacuum pump so as to draw a vacuum in order to depressurize the molding space. The material of the deaeration sheet is not particularly defined, but examples thereof include nylon fiber and glass fiber, and the woven structure is not defined, but woven fabric and nonwoven fabric are exemplified. The basis weight of the sheet is not particularly defined, but a sheet that can secure a suction circuit under a use reduced pressure is selected. For this purpose, as in the case of the porous film, it is desirable that the constituent fiber material is a non-adhesive material for the matrix resin.
[0012]
In this state, a matrix resin is injected from the resin injection port under a reduced pressure environment by vacuum suction to obtain a molded body. The viscosity at the time of resin injection needs to be 20 Poise or less, and a viscosity exceeding this value is unsuitable because an unimpregnated portion of the resin may occur in the sheet-like reinforcing fiber material. . Although it does not prescribe | regulate especially as a kind of resin used, Thermosetting resins, such as an epoxy resin, vinyl ester resin, unsaturated polyester resin, a phenol resin, are mentioned.
[0013]
In addition, as the material of the sheet-like reinforcing fiber material, carbon fiber woven fabric, non-woven fabric made of the same fiber, carbon fiber tow, glass fiber woven fabric, non-woven fabric, roving, alone or in combination, carbon wire, yarn glass It is preferable to mix and use the fiber. In particular, the use of carbon fiber is preferred for obtaining light weight and strength. When a sheet is formed by widening a plurality of carbon fiber tows, it is preferable to stack by changing the orientation of the fibers to be laminated because desired mechanical properties can be obtained in all directions. Usually, the number of filaments of one carbon fiber tow is in the range of 10,000 to 300,000, more preferably in the range of 50,000 to 150,000.
[0014]
As described above, the FRP molded body according to the present invention includes a sheet-like reinforcing fiber material alone or a structure in which a core material is interposed between reinforcing fiber materials. The whole of these reinforcing fiber materials and core materials are encapsulated sequentially from the inside in the order of a porous film, a deaeration sheet, and a bag film, and the inside covered with the bag film through the deaeration sheet is in a reduced pressure state. The matrix resin is injected into the bottom of the reinforcing fiber material, diffused in the surface direction of the reinforcing fiber material through the reinforcing fiber material by suction, and the resin is evenly impregnated into the reinforcing fiber material so that the whole is integrally molded To do. At this time, in the porous film and the degassing sheet, the gas flow in the molding space sucked through the degassing sheet is dispersed by the degassing sheet and the porous film, and uniform suction is performed throughout the reinforcing fiber material. The force works, so that the injected matrix resin is uniformly impregnated inside the reinforcing fiber material.
[0015]
In the molding method, without using the upper and lower molds that can be opened and closed, when using a mold that opens on one side alone, the porous film, degassing sheet, and bag film are laminated in that order on the open side, The periphery of the bag film is fixed to the mold through a sealing material, and the space formed between the mold and the porous film is defined as a sealed molding space, and the reinforcing fiber material is disposed in the sealed space. When interposing a core material inside, the outer shape of the core material forms the surface of the mold material, and the porous film, deaeration sheet, and bag film that are encapsulated via the sheet-like reinforcing fiber material are free. Therefore, the structure to be molded follows the outer shape of the core material.
[0016]
When the gas in the molding space is sucked through the degassing sheet, the matrix is drawn to the outside through the pores of the porous film, including the gas inside the reinforcing fiber material, and simultaneously injected toward the fiber material. The resin diffuses evenly in the fiber material and impregnates the entire reinforcing fiber material. At this time, as described above, the deaeration sheet having the deaeration circuit sucks air uniformly throughout the sheet through the porous film, and the pressure in the molding space is reduced to a predetermined value by the intake air. . While this reduced pressure is maintained, the required amount of injected matrix resin diffuses and impregnates uniformly throughout the fiber material. That is, the reinforcing fiber material is impregnated with the matrix resin very smoothly and uniformly, and a high-quality FRP structure is stably and efficiently manufactured at low cost.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 schematically shows a state of a long flat plate-shaped FRP molded body according to the first embodiment of the present invention during vacuum injection molding.
[0019]
The flat injection molding apparatus for a flat FRP molded body according to the present embodiment includes a flat plate-shaped mold 1 arranged horizontally, a porous film 2 provided on the upper surface of the mold 1 with a required molding space, and The degassing sheet 3 disposed on the upper surface of the porous film 2 and the bag film 4 disposed on the upper surface of the degassing sheet 3 are provided. At the time of molding, a flat reinforcing fiber material 5 is interposed in the forming space formed between the innermost porous film 2 and the flat plate mold 1, and after the reinforcing fiber material 5 is interposed. The peripheral edges of the deaeration sheet 3 and the bag film 4 are hermetically fixed to the upper surface of the mold 1 with a sealing material 6 interposed therebetween.
[0020]
On the other hand, a matrix resin injection port 1 a is formed through the flat plate-shaped mold 1, and the upper end of the injection hole 1 a becomes a bowl-shaped groove 1 b and extends in the longitudinal direction of the mold 1. Yes. The resin inlet 1a is connected to an external resin storage tank (not shown) through a pipe. An air inlet 7 for sucking the gas in the molding space is formed in a part of the peripheral edge of the deaeration sheet 3, and the air inlet 7 is provided outside via a bag film. The intake port is connected via a pipe 9. Here, a woven fabric or a non-woven fabric made of nylon fiber or glass fiber is used for the deaeration sheet 3, and it is used in combination with the porous film 2 to reinforce the reinforced fiber without causing unidirectional flow in the suction air. A uniform intake flow is generated over the entire surface of the material.
[0021]
The opening area of the holes formed in the porous film 2 is preferably ² to 1000 mm ² / m ² where the effect of vacuum suction is obtained, and the number of holes is 100 or less per 1 m ² within the above-mentioned range. It is desirable that When the number is 100 or more, the degassing sheet is blocked as the resin is sucked up, and good impregnation characteristics cannot be obtained. Thermosetting resins such as epoxy, unsaturated polyester, phenol, and vinyl ester are used as matrix resin for FRP. Of course, thermoplastic resins such as polyester, nylon, and ABS resin can be used alone, or a mixed resin of these and a thermosetting resin can be used.
[0022]
FIG. 2 schematically shows a second embodiment of the present invention. The mold 10 according to the present embodiment has a box shape with a molding space inside and an upper surface opened to the outside. In the present embodiment, the core material 16 is interposed between the reinforcing fiber materials 15. The first reinforcing fiber material 15a is placed on the upper surface of the core material 16 having a desired shape, and the second fiber reinforcing material 15a is disposed so as to cover the side surface and the lower surface of the core material 16, and this The mold 10 is accommodated in a molding space. As the core material, it is preferable to use a hard foam or cork for weight reduction, and a honeycomb made of an aluminum material can also be used. The core material 16 according to the present embodiment is formed with a resin flow hole 16a penetrating vertically in the center thereof.
[0023]
In this state, similarly to the first embodiment, the porous film 12, the degassing sheet 13 and the bag film 14 are sequentially laminated from the inside, and the peripheral edges of the porous film 12 and the degassing sheet 13 are sealed with the sealing material 11. Through the seal. Similarly to the first embodiment, the porous film 12 is provided with a large number of holes, and an air inlet 17 is formed in a part of the peripheral edge of the deaeration sheet 13, and is externally passed through the bag film 14. Is connected to a suction port of a vacuum pump 18 installed in a pipe 19 via a pipe 19. Further, in the present embodiment, a tubular resin inlet 10a of a matrix resin is arranged through the porous film 12, the degassing sheet 13 and the bag film 14 in this order toward the bottom of the box-shaped mold 10, and the same note. The inlet 10a is connected to a matrix resin tank (not shown) through a pipe (not shown).
[0024]
Now, by taking in air from the air inlet 17, the inside of the molding space is decompressed. While continuing this suction, the matrix resin is injected into the second reinforcing fiber material 15b disposed at the bottom of the mold 10 through the tubular injection port 10a. When the gas in the molding space is sucked from the suction port 17 formed at a part of the periphery of the degassing sheet 13, the sucked gas does not flow in one direction due to the presence of the porous film 12. The air is evenly sucked through a large number of holes formed in the. Therefore, the suction force is also made uniform throughout the fiber material, and as described above, the matrix resin injected into the lower reinforcing fiber material 15b is sucked and diffused throughout the second reinforcing fiber material 15b, and the first reinforcing fibers Reach material 15a. Also at this time, the suction force acts evenly on the entire first reinforcing fiber material 15a, so that the matrix resin is evenly sucked into the upper reinforcing fiber material 15a and is spread and impregnated.
[0025]
In this embodiment, the entire surface of the core material 16 is encapsulated with the reinforcing fiber material 15, but one surface of the core material 16 is exposed to the outside, or the fiber material 15 is disposed only on the upper and lower surfaces of the core material 16. You can also.
[0026]
Next, based on the Example of this invention, it demonstrates more concretely.
[Example 1]
1. A substrate A (glass chopped strand mat: 225 g / m ² ) with respect to the flat plate mold shown in FIG. 1 having a length of 1.8 m, a width of 0.9 m and a long groove for resin injection formed on one side thereof. The raw machine was arranged in the order of: / base material B (carbon fiber fabric manufactured by Mitsubishi Rayon: TRK910) / base material A. Next, a film (Tedola film made by DuPont) having 27 holes of about 1 mmφ at 200 mm intervals was covered from above, and each peripheral edge was adhesively fixed with a sealing material. When the porous film having the holes was measured, the opening area per 1 m ² was 13.09 mm ² and the numerical aperture was 16.7 pieces / m ² .
[0027]
Next, a deaeration sheet for a deaeration circuit (glass fabric: basis weight 250 g / m ² ) was placed thereon. Further, a bag film (Nylon film manufactured by Airtech Co., Ltd., thickness 0.002 inch) was placed on the sealing material to fix it to the sealing material. Thereafter, a suction port for evacuation was connected to a vacuum pump through a pipe in the bag film opposite to the resin inlet. Next, the vacuum pump was operated to check the airtightness of the bag film and the sealing material so that a predetermined reduced pressure was maintained, and the reduced pressure state of 750 mmHg was maintained for about 30 minutes. At this time, the matrix resin inlet was kept closed so that air could not enter.
[0028]
Next, injection | pouring was started from the resin injection port using the normal temperature hardening type vinyl ester resin whose viscosity in 22 degreeC is 10 poise. The vacuum pressure at the time of pouring was 300 mmHg, and the natural pouring method was adopted as the resin pouring method so that the pouring pressure range at the pouring port in a non-vacuum state was 0.05 to 0.01 MPa. After completing the matrix resin injection at a predetermined resin injection amount, the injection port was closed and the resin injection was stopped. Thereafter, the vacuum pressure was reduced to 500 mmHg to cure the resin.
The obtained laminated plate was a molded plate having a good surface state with almost no unimpregnated portion of resin.
[0029]
[Example 2]
For the mold shown in FIG. 2 having a length of 3.0 m and a width of 2.4 m, base material A (glass chopped strand mat: 225 g / m ² ) / base material B (carbon fiber fabric manufactured by Mitsubishi Rayon: TRK910) / The 2nd skin layer which consists of the 2nd reinforcement fiber material comprised in order of the base material A was arrange | positioned. Further, a core material was disposed thereon, and a first skin layer made of a first reinforcing fiber material in which the base material A / the base material B / the base material A were sequentially laminated in the same procedure as the second skin layer was disposed. Next, a film (Tedola film made by DuPont) having 42 holes of about 3 mmφ opened at intervals of about 500 mm was covered from above, and the periphery of the porous film was adhesively fixed with a sealing material. As a result of measuring the film with the holes, the opening area per 1 m ² was 41.23 mm ² and the numerical aperture was about 5.8 / m ² .
[0030]
Next, a sheet for deaeration (glass fabric: basis weight 250 g / m ² ) was placed thereon. Furthermore, a bag film (Nylon film made by Airtech Co., Ltd., thickness 0.002 inch) was placed on the sealing material and adhered to the sealing material. After that, seven resin injection ports are provided at intervals of about 500 mm on one side in the length direction, and an air suction port is opened at the end of the bag film on the opposite side, and a vacuum pump is connected there through a pipe. Connected. Next, the vacuum pump was operated, the airtightness of the bag film and the sealing material was confirmed so that the reduced pressure was maintained, and the normal pressure state of 750 mmHg was maintained for about 60 minutes. At this time, each resin inlet was kept closed so that air could not enter.
[0031]
Next, injection of the resin was started from the resin injection port using a normal temperature curing type vinyl ester resin having a viscosity at 25 ° C. of 5 poise. The vacuum pressure at the time of pouring was 400 mmHg, the natural pouring method was adopted as the resin pouring method, and the pouring pressure range at the pouring port in a reduced pressure state was set to 0.05 to 0.01 MPa. After a predetermined resin injection amount was injected, the injection port was sequentially closed to stop the resin injection. Thereafter, the vacuum pressure was kept at 650 mmHg to cure the matrix resin.
When an unimpregnated state of the obtained sandwich laminate was measured by ultrasonic waves, it was found that a sandwich molded body having a good surface state in which the resin was almost impregnated was obtained.
[0032]
As described above, according to the present invention, the unimpregnated portion of the resin, which has been a problem in the past, is almost eliminated, and molding with less odor and excellent productivity is possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a molding state during FRP molding according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically showing a molding state during FRP molding according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,10 Mold 1a Resin injection port 1b Groove 10a Tubular injection port 2,12 Porous film 3,13 Deaeration sheet 4,14 Bag film 5,15 Reinforcement fiber material 15a, 15b Upper and lower reinforcement fiber material 6 Sealing material 7 , 17 Intake port 8, 18 Vacuum pump 9, 19 Piping 11 Sealing material 16 Core material 16a Resin flow hole

Claims (8)

A bag film in which a sheet-like reinforcing fiber material is arranged in the molding space of the mold and encapsulates the fiber material, a reduced pressure source for depressurizing the bag film, and an inlet for injecting a matrix resin into the fiber material A vacuum injection molding apparatus for fiber-reinforced plastic having
One side of the molding space is opened,
A porous film having a large number of small holes is disposed between the open side surface of the fiber material and the bag film whose periphery is hermetically fixed to a mold ,
A degassing sheet having a degassing circuit is disposed between the porous film and the bag film,
The reduced pressure source is connected to a sealed space between the bag film and the degassing sheet,
The resin injection port is arranged toward the bottom of the fiber material opposite to the porous film,
An apparatus for molding a fiber-reinforced plastic molded product.   The molding apparatus according to claim 1, wherein the degassing sheet is a glass fiber fabric. The porous film forming apparatus according to claim 1 or 2, characterized by having an opening area of 2～1000Mm ² per 1 m ^2. The forming device according to claim 1, wherein the porous film has 100 or less holes per 1 m ² . A sheet-like reinforcing fiber material is arranged in the molding space of the mold, the fiber material is hermetically encapsulated with a bag film, a matrix resin is injected into the fiber material, and the bag film is depressurized, In a vacuum injection molding method for molding fiber reinforced plastic,
Opening one surface of the molding space;
Arranging a reinforcing fiber material in the mold,
To distribution in the porous film having a large number of small holes on the surface of the fibrous material,
Arranging a degassing sheet having a degassing circuit on the surface side of the porous film;
Arranging the bag film on the surface side of the degassing sheet so that the molding space is hermetically sealed;
The molding space is kept under reduced pressure via the degassing sheet by an external pressure source, and the resin viscosity at the time of resin injection is 20 Poise or less at the bottom of the fiber material in the molding space under reduced pressure. Injecting matrix resin,
A method for forming a fiber-reinforced plastic molded article comprising: The molding method according to claim 5, wherein the sheet-like reinforcing fiber material is a multilayer. Be secured airtightly periphery of the bag film through the sealing material into the mold,
The shaping | molding method of Claim 5 or 6 which comprises these. The molding method according to claim 7 , comprising disposing a core material between the sheet-like reinforcing fiber materials.

Images