JP2009028989A - Integrally molding method of frp molded article by resin transfer molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and rational molding process for obtaining an integral FRP molded article from a fiber-reinforced material, a matrix resin and a primary molding member. <P>SOLUTION: An integrally molding method of the FRP molded article by a resin transfer molding method is characterized by that when the fiber-reinforced material, the matrix resin and the primary molding member are subjected to secondary molding by a resin transfer molding method to obtain the integral FRP molded article, a molding die capable of independently molding the integral FRP molded article and the primary molding member from one molding die is used and secondary molding for obtaining the integral FRP molded article and primary molding for obtaining the primary molding member used in following secondary molding are simultaneously performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for integrally forming an FRP molded product composed of a fiber reinforcing material, a matrix resin, and a primary molded member by a resin transfer (RTM) molding method.

Fiber reinforced plastic (FRP) is a thermosetting resin such as unsaturated polyester resin, epoxy resin and polyimide resin, matrix resin of thermoplastic resin such as polyethylene, polypropylene, polyamide, PPS, PEEK, carbon fiber, glass fiber In recent years, it is used in a wide range of fields from the aerospace industry to the general industrial field because it is made of a fiber reinforcing material such as an aramid fiber and is lightweight and excellent in strength properties. Various methods and means are known as the molding method, and the RTM molding method is attracting attention as a molding method particularly suitable for high-mix medium-volume production.

In the resin transfer (hereinafter sometimes abbreviated as RTM) molding method, a preform or sheet shape in which a fiber reinforcing material is shaped into a molded product shape inside a mold (molding die) composed of an upper die and a lower die. After placing the fiber reinforcing material and clamping the mold, the cavity formed by the upper mold and the lower mold is exhausted from the mold outlet through the discharge hose, while the mold inlet Then, a resin is injected into the cavity through an injection hose to impregnate the fiber reinforcing material, and if necessary, heated and pressurized to be cured. Such an RTM molding method has a feature that a complex product that has been conventionally manufactured by assembling several parts can be integrally molded (for example, see Patent Documents 1 and 2).
2006-150614 2007-76307

As described above, the RTM molding method can integrally mold a complex FRP molded product. For example, a fiber reinforcing material, a matrix resin, and a secondary material are molded by the RTM molding method to obtain an integrated FRP molded product. Convenient to get. As the secondary material, for example, there is a weight for balancing or balancing the molded product, and such a weight is usually obtained by molding with another mold (hereinafter referred to as a primary molded member). Therefore, in such a case, two types of molding processes, that is, a molding process for obtaining a primary molded member (in the present invention, this is called primary molding), a fiber reinforcing material, a matrix resin, and a primary molded member are integrated. A step of molding (in the present invention, this is called secondary molding) is required. The inventors of the present invention have intensively studied about simplification and rationalization of the molding process, and have reached the present invention.

An object of the present invention is to provide a simple and rational molding method for obtaining an integrated FRP molded product from a fiber reinforcing material, a matrix resin, and a primary molded member.

According to the first aspect of the present invention, when the fiber reinforcing material, the matrix resin, and the primary molded member are secondarily molded by the resin transfer molding method to obtain an integrated FRP molded product, the integral molding is performed with one molding die. FRP molded product and the primary molded member are used to form the primary molded member, and the primary molded member used in the subsequent secondary molding and the secondary molding for obtaining the integrated FRP molded product are obtained. Is an integrated molding method for FRP molded products by a resin transfer molding method, characterized in that primary molding is simultaneously performed.

The invention according to claim 2 is characterized in that the primary molded member serves as a weight for balancing the FRP molded product, and the FRP molded product is integrated by the resin transfer molding method according to claim 1. This is a chemical molding method. In the molding method of the present invention, auxiliary materials other than the primary molded member may be used in combination.

According to the present invention, when an objective FRP molded product, that is, a molded product composed of a fiber reinforcing material, a matrix resin, and a primary molded member is integrally formed by the RTM molding method, a primary molded member used in the next molding is obtained at the same time. Therefore, it is not necessary to mold the primary molded member in a separate process, and the molding process can be rationalized and simplified.

In the present invention, when a fiber reinforcing material, a matrix resin, and a primary molded member are secondarily molded by an RTM molding method to form an integrated FRP molded product, the integrated FRP molded product and the primary molded member with one molding die, For example, using a molding die that can independently mold weights for balancing the FRP molded product, secondary molding to obtain the integrated FRP molded product, and the primary used in the next secondary molding. This is a molding method comprising simultaneously performing primary molding for obtaining a molded member. In the present invention, the primary molded member refers to a member that is used simultaneously as an auxiliary material when a FRP molded product is molded from a fiber reinforcement and a matrix resin, and is also obtained by the RTM molding method. . Specifically, for example, there is a weight for balancing or balancing the molded product, which is made of a fiber reinforcing material and the matrix resin, or made of only the matrix resin, but is not limited to this.

The RTM molding method used in the present invention is a preform or sheet shape of a fiber reinforcement made of long fibers or short fibers shaped into a molded product, inside a mold (molding die) consisting of an upper mold and a lower mold. In this molding method, after placing and clamping the mold, the resin is injected from the resin inlet under reduced pressure to impregnate the fiber reinforcing material, and after heat curing, the mold is opened and demolded. A so-called prepreg is not required, and it is characterized in that a molded product with good productivity and good quality on both sides can be obtained compared to the autoclave method and the hand lay-up method.

The present invention will be described below with reference to the drawings. FIG. 1 is a partial view showing a state in which a cavity 2 corresponding to the shape of a molded product is formed in a lower mold 1 of a mold used in an RTM molding method. In normal RTM molding, an FRP molded product is molded by the above-described method using a lower mold of a mold as shown in FIG. 1 and an upper mold corresponding thereto. That is, a preform or sheet-like fiber reinforcing material is laid on the inner surfaces of the upper and lower mold cavities, and a primary molded member or the like is disposed therein if necessary, and then the matrix resin is introduced from the resin inlet. The resin is injected under reduced pressure and heated if necessary to cure the resin, thereby obtaining an FRP molded product in which the fiber reinforcing material, the matrix resin, the primary molded member and the like are integrated.

In contrast to the usual RTM molding method as described above, a mold (lower mold) as shown in FIG. 2 is used in the present invention. In FIG. 2, 1 and 2 are the same as those in FIG. 1, but 3 shows a cavity for molding the primary molded member. The cavity 3 for molding the primary molded member is formed in the same mold as the cavity 2 for molding the final molded product (integrated FRP molded product) (the corresponding upper mold in FIG. 2). Is omitted). Therefore, when an integrated FRP molded product is formed in the cavity 2, a resin is simultaneously injected into the cavity 3, and if necessary, the resin is cured by heating, so that an integrated FRP molded product can be obtained in the cavity 2. In the cavity 3, a primary molded member used in the next molding step is obtained.

The matrix resin used in molding the FRP molded product by the RTM molding method of the present invention includes a thermosetting resin and a thermoplastic resin, and a thermosetting resin is preferred. A thermosetting resin and a thermoplastic resin can also be mixed and used. Preferred thermosetting resins include epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, maleimide resin and cyanate ester resin. Resins and the like may be used, and these thermosetting resins may be blended in appropriate amounts. Of these resins, epoxy resins and vinyl ester resins excellent in heat resistance, elastic modulus, and chemical resistance are preferable. These thermosetting resins may contain a curing agent, a curing accelerator and the like.

As the fiber reinforcing material, materials used for ordinary fiber reinforcing materials such as carbon fiber, glass fiber, aramid fiber, boron fiber, metal fiber and the like can be used. Among these, carbon fiber, glass fiber, and aramid fiber are preferable. The form of the fiber reinforcement is not particularly limited, and a woven fabric or a nonwoven fabric can be used. Examples of the woven fabric include a plain woven fabric, a twill woven fabric, a satin woven fabric and the like, or a uniaxial woven fabric and a multiaxial woven fabric. The reinforcing fiber strands forming the woven fabric are preferably 500 to 24,000 monofilaments having a fiber diameter of 4 to 8 μm per bundle. The thickness of the woven fabric or the like is appropriately selected depending on the use of the molded product, and is not particularly limited. The uniaxial woven fabric refers to a woven fabric in which reinforcing fiber strands arranged in parallel to each other are knitted with nylon yarn, polyester yarn, glass fiber yarn or the like. The multiaxial woven fabric refers to a woven fabric in which reinforcing fiber strands arranged in parallel to each other are laminated at different angles and knitted with nylon yarn, polyester yarn, glass fiber yarn or the like.

The mold (or mold) used in the RTM molding method of the present invention is not particularly limited, but a metal mold such as a highly rigid metal mold or FRP mold is used. The upper mold and the lower mold may be subjected to a release treatment using a known release agent such as silicone wax, and then a fiber reinforcing material may be laid and laminated. Moreover, a peel cloth or the like may be stacked on the fiber reinforcement for the purpose of improving the releasability when taking out the molded product. Hereinafter, the present invention will be described in detail by way of examples.

(1) Mold and its lower mold as shown in FIG. 2, a cavity 3 for molding a primary molded member, and a cavity 2 for molding a final secondary molded product (integrated FRP molded product) However, the mold 1 formed in the same mold was used (the corresponding upper mold is omitted in FIG. 2).

The cavities 2 and 3 were provided with a resin injection port and a discharge port, respectively. A push-one was inserted into each resin inlet and outlet, and a urethane hose was inserted into the mold to reduce the pressure in the cavity and to inject and discharge the resin. The cavities 2 and 3 have a structure in which resin enters the cavity 3 simultaneously with the cavity 2 by a resin flow path (groove) provided in the mold.

The base material composed of (2) base fiber reinforcement, Nitto Boseki made of glass fiber base material (generic grade) WR570-B100S (basis weight 570 g / ^{m 2} or equivalent) and WLA180M110H974 (basis weight 200 g / ^{m 2} or equivalent) These were stacked and placed in the cavity 2. On top of that, a primary molding member (a mass of resin molded in a cavity 3 described later having a width × length of 30 mm × 1100 mm) and a hard foamed urethane core were placed, and the mold was closed.

(3) Molding processing A urethane hose was inserted into the resin inlet and outlet, the hose on the resin inlet side was closed with a clamp, etc., and the hose end on the resin outlet side was connected to a vacuum pump. The vacuum pump was operated and the cavities 2 and 3 were evacuated. Thereafter, the tip of the resin injection hose was inserted into the resin tank, and the clamp was released. Resin was poured into cavities 2 and 3 from the resin tank using vacuum pressure. As the resin, a mixed liquid in which 100 parts by mass of Adeka Resin EP-4901 (manufactured by Adeka), which is an epoxy resin, and 20 parts by mass of 1,3-BAC (manufactured by Mitsubishi Gas Chemical) was used. After the cavities 2 and 3 were sufficiently filled with the resin, the hose on the resin inlet side and the outlet side was closed with a clamp or the like. The cavities 2 and 3 were sealed, and the resin injected into the cavities 2 and 3 was subsequently cured.

(4) After the demolding resin was sufficiently cured, the mold was opened and demolding was performed. From the cavity 2, an FRP molded product in which the fiber reinforcement, the matrix resin, and the primary molded member were integrated was obtained. On the other hand, from the cavity 3, a primary molded member made only of a matrix resin (a lump of resin having a width x length of 30 mm x 1100 mm) was obtained.

FIG. 1 is a partial view showing a state in which a cavity corresponding to a shape of a molded product is formed in a lower mold, which is a mold used in a normal RTM molding method. FIG. 2 is a partial view showing a mold used in the present invention, in which a cavity for forming a primary molded member is formed in the lower mold in addition to the cavity corresponding to the shape of the molded product. .

Explanation of symbols

1 Mold lower mold 2 Cavity corresponding to the shape of molded product 3 Cavity for molding primary molded parts

Claims (2)

When the fiber-reinforced material, the matrix resin, and the primary molded member are secondarily molded by the resin transfer molding method to obtain an integrated FRP molded product, the integrated FRP molded product and the primary molded member are independently formed with a single mold. Using a mold that can be molded, secondary molding for obtaining the integrated FRP molded product and primary molding for obtaining the primary molded member used in the next secondary molding are performed simultaneously. Integrated molding method for FRP molded products by resin transfer molding. 2. The method for integrally forming an FRP molded product by the resin transfer molding method according to claim 1, wherein the primary molded member serves as a weight for balancing the FRP molded product.

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