JP4052381B2 - Resin coat molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin coat molding method in which a resin layer is formed by applying a resin to one surface of a mold, and a fiber reinforcing material is impregnated with a resin of the resin layer and heat-cured.
[0002]
[Prior art]
Conventionally, prepregs are used for the production of fiber-reinforced composite materials. A prepreg is a molding material in which a fiber reinforced material is impregnated with a thermosetting resin and has undergone a curing reaction to such an extent that it can be easily handled by hand. A prepreg composed mainly of a fiber reinforcing material such as carbon fiber, boron fiber, or aramid fiber and an epoxy resin is used.
[0003]
The prepreg is formed by heat-curing a plurality of prepregs laid on the inner surface of the mold under pressure. The prepreg has a tack on the surface due to its structure, and air is caught between the prepregs when laminating. For this reason, in the case of vacuum bag molding in which pressure molding is performed at atmospheric pressure without sufficiently applying pressure from the outside, voids due to residual air are generated in the resulting molded product, and the physical properties of the molded product are reduced. There is a problem of end.
[0004]
In order to prevent the generation of such voids, International Publication WO 00/27632 discloses a molding material in which a fiber reinforcing material is stacked on at least one surface of a resin layer. Japanese Patent Application Laid-Open No. 5-269909 also discloses a method using a fiber film and a resin film of a thermosetting resin instead of the prepreg. In this method, a fiber reinforcing material and a resin film are stacked and then heated to impregnate the resin of the resin film into the fiber reinforcing material and cured to obtain a molded product.
[0005]
The methods using these molding materials can suppress the generation of voids as compared with conventional prepregs. Further, there is an advantage that a special product such as an autoclave is not required and a molded product can be easily obtained by vacuum bag molding using a curing furnace, and the product can be obtained at a low production cost. However, the resin used as the molding material must be formed into a film, and the usable resin is limited. Moreover, in order to maintain the shape of the film at room temperature, it is necessary to store it at a low temperature, and it is difficult to handle the resin because its life is short.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a molding method that does not require a resin film that is difficult to handle and does not generate voids due to remaining air.
[0007]
[Means for Solving the Problems]
The present invention for solving the above problems is described below.
[0008]
[1] A resin layer is formed on one surface of a mold, a fiber reinforcement sheet is stacked on the resin layer, a bag is stacked on the stacked fiber reinforcement sheet, and the periphery of the bag is hermetically sealed to the mold Then, a resin coat molding method in which the fiber reinforcing material sheet is impregnated and cured by evacuating and heating between the bag and the mold.
[0009]
[2] After forming a resin layer on one surface of the mold and stacking a fiber reinforcing material sheet on the resin layer, a bag is stacked on the stacked fiber reinforcing material sheet, and the periphery of the bag is attached to the other surface of the mold. A resin coat molding method in which a fiber-reinforced material sheet is impregnated with a resin of a resin layer and cured by air-tightly sealing to another covered bag, then exhausting between the bag and the mold and heating.
[0010]
[3] A resin layer is formed on one surface of the mold, and a fiber reinforcing material sheet is stacked on the resin layer, and then a bag is stacked on the stacked fiber reinforcing material sheet and the periphery of the bag is hermetically sealed to the mold A resin coat molding method in which the space between the bag and the mold is evacuated and heated under pressure in an autoclave so that the resin of the resin layer is impregnated into the fiber reinforcing material sheet and cured.
[0011]
[4] After forming a resin layer on one surface of the mold and stacking a fiber reinforcing material sheet on the resin layer, a bag is stacked on the stacked fiber reinforcing material sheet, and the periphery of the bag is attached to the other surface of the mold. A resin coat molding method in which a fiber reinforcing material sheet is impregnated with a resin of a resin layer and cured by evacuating between the bag and the mold and then heating under pressure in an autoclave.
[0012]
[5] The resin coat molding method according to any one of [1] to [4], wherein the resin layer is formed by a brush coating method or a spraying method.
[0013]
[6] The viscosity of the resin forming the resin layer at 25 ° C. is 100 Pa · s to semi-solid, and the viscosity is reduced to 0.1 to 10 Pa · s during molding heating. The resin coat molding method as described.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As the resin for forming the resin layer, a commonly used thermosetting resin can be used. Specifically, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, resin obtained by prepolymerizing maleimide resin and cyanate ester resin, etc. In the present invention, a mixture of these resins can also be used. When a fiber reinforced composite material is used, an epoxy resin composition excellent in heat resistance, elastic modulus, and chemical resistance is preferable. These thermosetting resins may contain a curing agent, a curing accelerator and the like.
[0015]
The curing temperature of the resin is preferably adjusted to 60 to 180 ° C, more preferably 70 to 130 ° C.
[0016]
The resin viscosity at 25 ° C. is preferably 100 Pa · s to semi-solid in order to prevent dripping of the resin applied to the mold.
[0017]
Moreover, the thing whose resin viscosity reduces to 0.1-10 Pa.s at the time of shaping | molding heating is preferable. A resin having such a viscosity can be suitably used when applied to a mold.
[0018]
As the fiber reinforcing material sheet, reinforcing fibers such as carbon fibers, glass fibers, aramid fibers, boron fibers, metal fibers and the like can be used. Among these, carbon fiber, glass fiber, and aramid fiber are preferable. Moreover, as for the form of these fiber reinforcement material sheets, arbitrary processed goods, such as what was arranged in one direction or those arranged in multiple directions, a woven fabric, a knitted fabric, and a nonwoven fabric, can be utilized.
[0019]
Basis weight of the fibrous reinforcement sheet is preferably ^{200~3000g / m 2, 400~2000g / m} 2 is more preferable.
[0020]
The resin coat molding method of the present invention will be described below with reference to FIG.
[0021]
First, a resin is applied to the mold to a required thickness along one surface of the mold 2 to form the resin layer 4, and the fiber reinforcing material sheets 6 are stacked on the resin layer 4 (FIG. 1A). There is no particular limitation on the mold, and known molds can be used.
[0022]
As a method for forming the resin layer on the mold, any forming method such as a brush coating method or a spraying method can be used. The resin amount of the resin layer is preferably 35 to 55% of the total weight of the fiber reinforcing material to be stacked and the resin amount of the resin layer.
[0023]
Moreover, it is preferable that the resin layer formed on a type | mold has an appropriate tackiness at room temperature. A resin layer having an appropriate tackiness is preferable because it improves workability when stacking fiber reinforcing materials.
[0024]
As a method of forming a resin layer having an appropriate tackiness at room temperature, a method of heating a high-viscosity resin to a low viscosity and applying it to a mold, and then returning to room temperature to obtain a resin layer having an appropriate tackiness, Applying a low-viscosity resin to the mold and partially polymerizing the resin to such an extent that the fiber reinforcing material is impregnated when heated, a method for forming a resin layer having an appropriate tackiness, and utilizing the thixotropic property of the resin Examples thereof include a method for forming a resin layer having tackiness.
[0025]
After the fiber reinforcing material sheets 6 are stacked, the bag 8 is placed on the fiber reinforcing material, and the periphery of the bag 8 is hermetically sealed with the mold 2 and sealed (FIG. 1B). After sealing the fiber reinforcement sheet with the bag, the gas between the mold 2 and the bag 8 is exhausted to reduce the pressure (FIG. 1 (c)). By reducing the pressure between the mold and the bag, the bag is deformed, and the fiber reinforcement adheres to the resin layer formed on the mold.
[0026]
The material of the bag is not particularly limited, and commonly used known materials can be used. Furthermore, the shape of the bag is not particularly limited, and a sheet shape, a bag shape, or the like can be appropriately selected and used depending on the shape of the mold or the target molded product. The bag may be sealed so that the fiber reinforcing material can be brought into close contact with the resin layer formed on the mold by decompression. For example, a method of directly sealing a bag to a mold with a sealant, a method of inserting a mold in which fiber reinforcements are stacked into a bag-like bag and sealing the periphery of the bag to the mold, and a single bag placed on top of the fiber reinforcement And a method of hermetically sealing other bags disposed on the other surface of the mold with a sealant. The method of sealing the bags together and covering the entire mold with the bag is when there is a jig mounting hole that penetrates the mold and cannot be sealed even when directly sealed to the mold, or when the mold is made of a breathable material, etc. Is particularly effective.
[0027]
Thereafter, the resin layer 4 sealed with the bag 8 and the fiber reinforcing material sheet 6 are heated in an oven or an autoclave to obtain a molded product 12 composed of the fiber reinforced resin layer 13 (FIG. 1 (d)). By heating, the resin of the resin layer is sufficiently impregnated into the fiber reinforcing material sheet and cured to form a molded product. The heating temperature is preferably 60 to 200 ° C. Moreover, when using an autoclave, it is preferable that a pressurization pressure shall be 0.1-0.5 Mpa. When processing in an oven or an autoclave, it is preferable to perform the processing after or while exhausting the gas between the mold and the bag.
[0028]
Furthermore, in the molding method of the present invention, a foam core material may be inserted inside. An example of a molding method using a foam core material is shown in FIG.
[0029]
Resin is applied onto the mold 28 to form the resin layer 14a, and the fiber reinforcing material sheet 16a and the foam core material 24 are laid. Further, a resin is applied on the foam core material 24 to form a resin layer 14b, and a fiber reinforcing material sheet 16b is laid on the resin layer (FIG. 2A). Then, after sealing with the bag 18, the inside of the bag is decompressed and heat-molded in the same manner as shown in FIG. 1 to obtain a molded product 22 composed of the fiber reinforced resin layers 26a and 26b and the foamed core material 24 (FIG. 2). (B)). Examples of the foam core material include urethane foam, vinyl chloride foam, polymethacrylimide foam, acrylic foam, phenol foam, and polystyrene foam. Also, balsa material can be used.
[0030]
In the resin coat molding method of the present invention, a gel coat may be used according to the use of the molded product. When the gel coat is used, the gel coat is applied on the mold subjected to the release treatment to form a gel coat layer, and the resin layer is formed on the gel coat layer. The gel coat layer is polymerized and gelled at room temperature or by heating, and remains on the surface of the molded product without being impregnated with the fiber reinforcement, so that the surface of the molded product can be made smooth. When a gel coat is applied, a spray method or a brush coating method is usually used. In the formation of the resin layer, if the spraying method or the brush coating method is used, the gel coat layer and the resin layer can be formed with the same equipment, which is preferable in terms of productivity.
[0031]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0032]
Example 1
80 parts by mass of Epicoat 834 (manufactured by Japan Epoxy Resin Co., Ltd.) heated to 80 ° C., 20 parts by mass of Epicoat 1001 (manufactured by Japan Epoxy Resin Co., Ltd.), and 5 parts by mass of Anchor 1040 (manufactured by Air Products Japan) are kneaded. And it apply | coated with the brush so that it might become 1500 g / m < ² > on the flat aluminum plate which carried out the mold release process. Then, after the applied resin returned to room temperature and produced an appropriate tack, 10 sheets of carbon fiber fabric W-3101 (manufactured by Toho Tenax Co., Ltd.) cut to a size of 500 mm × 500 mm were laminated, and a peel cloth was laminated thereon. did. Thereafter, the entire laminated material was covered with a nylon bag (WRIGHTLON # 7400, manufactured by AIRTECH), the mold and the nylon bag were sealed with a sealant tape, and the inside of the bag was decompressed with a vacuum pump.
[0033]
Thereafter, it was cured by heating in a curing furnace at 130 ° C. for 2 hours while reducing the pressure with a vacuum pump to obtain a CFRP plate having a thickness of 2.2 mm.
[0034]
【The invention's effect】
In the molding method of the present invention, a resin layer is formed on a mold, a fiber reinforcing material is stacked thereon, and then heated to impregnate the resin of the resin layer into the fiber reinforcing material sheet. There is no. For this reason, it is not necessary to store at low temperature in order to keep the state of the semi-cured resin film until the time of use as in the past, and it is easy to handle because the prepared resin can be used immediately, which is advantageous in terms of resin life. . Even if vacuum bag molding is performed, voids unlike conventional prepregs are not generated, and a high-quality molded product can be obtained.
[Brief description of the drawings]
FIG. 1 is a flow chart showing an example of a molding method of the present invention, in which (a) is a cross-sectional view showing a state in which a resin layer is formed and fiber reinforcing materials are stacked, and (b) is a fiber reinforcing material that is a bag and a mold. FIG. 4C is a cross-sectional view showing a state in which the space between the bag and the mold is evacuated, and FIG. 4D is a cross-sectional view showing a state in which a molded product is impregnated with resin. .
FIG. 2 is a flowchart showing another example of the molding method of the present invention, and is a diagram showing a molding method using a foamed core material.
[Explanation of symbols]
2, 28 Mold 4, 14a, 14b Resin layer 6, 16a, 16b Fiber reinforcement sheet 8, 18 Bag 10, 20 Sealant 12, 22 Molded product 13, 26a, 26b Fiber reinforced resin layer 24 Foam core material

Claims (5)

A carbon fiber sheet having a basis weight of 200 to 3000 g / m ² is formed on one surface of the mold by applying or spraying an epoxy resin having a viscosity of 0.1 to 10 Pa · s at 60 to 200 ° C. After stacking the bags, the bag is stacked on the stacked carbon fiber sheets, the periphery of the bag is hermetically sealed to the mold, the space between the bag and the mold is exhausted, and the resin in the resin layer is heated by carbon fiber. A resin coat molding method in which a sheet is impregnated and cured, wherein the resin amount of the resin layer is 35 to 55% of the total weight of the carbon fiber sheet and the resin layer.   The resin coat molding method according to claim 1, wherein the curing temperature of the epoxy resin forming the resin layer is adjusted to 60 to 180 ° C.   The resin coat molding method according to claim 1, wherein the epoxy resin contains a curing agent and a curing accelerator.   The resin coat molding method according to claim 1, wherein the heating temperature is 60 to 200 ° C. After the gel coat is applied on one surface of the mold, the gel coat is polymerized at room temperature or by heating to form a gel coat layer, and an epoxy resin having a viscosity of 0.1 to 10 Pa · s at 60 to 200 ° C. is formed on the gel coat layer. A resin layer is formed by coating or spraying, a carbon fiber sheet having a basis weight of 200 to 3000 g / m ² is stacked on the resin layer, and then a bag is stacked on the stacked carbon fiber sheet and the periphery of the bag is molded. Is a resin coat molding method in which the carbon fiber sheet is impregnated and cured by heating, exhausting between the bag and the mold, and heating, and the amount of resin in the resin layer is the carbon fiber sheet And a resin coat molding method of 35 to 55% of the total weight of the resin layer.

Images