JP3216188B2 - Molding method of FRP molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of setting a preformed glass fiber mat in a mold and injecting a resin to form an FRP product.

[0002]

2. Description of the Related Art A method called resin transfer molding (hereinafter referred to as RTM) is one type of manufacturing method for molding a resin molded product by injecting a resin into a mold. This R
The TM method will be described with reference to FIG. 4 showing a mold for a front end panel of an automobile. A convex mold 1 which is usually an upper mold and a concave mold 2 which is usually a lower mold are prepared, and the molds 3 of both molds are cleaned and a release agent is applied. Next, a gel coat is sprayed on the molded portion 3 of the concave mold 2 with a spray gun or the like, and the initial curing of the gel coat is waited for several minutes. Next, a glass mat as a reinforcing material of the product is set on the gel coat. Next, both types 1,
2 is closed and the mold is clamped at the parting surface P, a resin injection nozzle is connected to the injection port 4 of the upper die 1, and the injection machine is operated to inject the resin and wait for the resin to be completely cured. After a lapse of a predetermined time, the mold is opened and the product is taken out.

As the reinforcing glass fiber used in the RTM, a preform mat preformed to a uniform thickness in accordance with the product shape is used in each case. Japanese Patent Application Laid-Open No. 1-222111 discloses that a resin-rich portion is produced in a product by stacking several reinforcing fiber mats, sewing them in a quilting shape, and using a preform mat adapted to the shape of a molded product. A prevented resin injection method is described. Also, JP-A-63-87215
In the publication, when a triangular glass plate or the like is placed in a cavity and molten resin is injected from a central position on the back surface to form a frame portion on the entire back surface and the peripheral portion on the front surface, the molten resin is injected. The thickness of the cavity from the position to the peripheral edge is reduced, the flow of the resin is adjusted by forming the cavity to the peripheral edge to be thicker, and no void is left on the back side of the molded product. An injection molding method for forming a frame around the entire periphery of a molded article is described.

[0004]

In the case of a product having a complicated shape, it is difficult to determine the position of the resin injection port in the RTM. If the setting is incorrect, the resin does not flow evenly in the mold, and the resin is in a cavity. Is not completely filled, that is, a so-called short circuit occurs. For this reason, a multipoint injection method in which several resin injection ports are provided is used, but the mold structure becomes complicated, and the number of steps for setting nozzles to the injection ports and cleaning the nozzles after injection is doubled. In the molding method described in JP-A-63-87215, since the flow of the resin is controlled to be uniform by changing the thickness of the cavity of the molding die, it is necessary to remodel the molding die. Cost increase is required. Further, the method described in the above-mentioned Japanese Patent Application Laid-Open No. 1-222111 does not uniformly control the flow of the resin in the mold. In addition, since several reinforcing fiber mats are overlapped and sewn in a quilting shape. It takes time and trouble, and the flow of the resin in the sewn portion may be hindered.

According to the present invention, when preforming, the thickness of the preform mat is partially changed, and the preform mat is set in a normal molding die, so that the flow of the resin in the mold can be properly controlled. It is an object of the present invention to provide an FRP molding method capable of adjusting and completely filling a molding portion in a mold with a resin.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method of preforming a reinforcing fiber mat to form a preform mat.
An FRP molded product characterized by forming a concave portion extending from a portion corresponding to a resin injection port of a molding die to a peripheral portion of the molded product, setting the preform mat in the molding die, and injecting a resin from the resin injection port. This is a molding method.

[0007]

The resin injected from the resin injection port penetrates into the reinforcing fibers, flows through the concave portion formed in the preform mat, flows to a distant portion, and penetrates into the reinforcing fibers at that portion. Therefore, the resin is filled up to the corner of the molded portion.

[0008]

FIG. 1 shows a preform mat used to mold a front end panel of an automobile.
When the preform mat 5 is molded, a concave portion 6 is formed at a portion corresponding to the resin injection port 4 in FIG. 4, and a concave portion 7 in the radial direction is formed from the concave portion 6 and concentric with the concave portion 7 by being connected to the concave portion 7. A large number of recesses 8 in different directions are molded together. The recesses 7 and 8 form a flow path through which the resin that has entered the recess 6 from the resin injection port easily flows to a portion far from the resin injection port, and depends on the position of the resin injection port and the shape of the molded portion. It can be set appropriately. When the preform mat 5 is set in a molding die and the resin is injected, the resin infiltrates into the glass fiber below the concave portion 6 and, as shown in an enlarged cross section in FIG. 5, the resin branches off from the concave portion 7 to the concave portion 8 as shown by an arrow in FIG.
Since the resin uniformly flows to the far part in the mold and penetrates into the glass fiber at that part, the resin is filled up to the corner of the molding part, and so-called short-circuit does not occur in the molding.

FIG. 3 shows a preform mat 9 used for molding an engine hood for an automobile. Similar to the embodiment shown in FIG. 1, a recess 6 is formed at a portion corresponding to a resin injection port. A plurality of concavities 7 are provided in a radial direction from the first direction, and a large number of concentric recesses 8 connected to the concave parts 7 are provided. These recesses 6, 7, 8 can be easily formed by strongly pressing the glass fiber during the molding of the preform mat, and can be modified using a heated iron trowel. is there.

The present invention relates to an engine hood, a fender,
Applicable to the molding of automotive outer panels such as roofs and trunk lids, and also applicable to automotive structural members such as suspensions, lower arms, upper arms, and frames. It is. Further, the present invention can be applied to the molding of architectural structures other than automobile parts such as engine hoods.

[0011]

As described above, according to the present invention, the flow of the resin in the molding die can be properly adjusted only by partially changing the thickness of the preform mat without modifying the conventional molding die. It can be adjusted and the molded part can be completely filled with resin, so that molding defects can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of the present invention.

FIG. 2 is a partially enlarged view of line XX in FIG. 1;

FIG. 3 is a plan view of another embodiment of the present invention.

FIG. 4 is a sectional view of an RTM mold.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Convex type 2 Concave type 3 Molding part 4
Resin inlet 5, 9 Preform mat 6 Resin inlet recess 7 Radial recess 8 Annular recess

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/14-45/16 B29C 39/00-39/10 B29C 67/12-67/18 B29K 105: 06-105: 22 B29L 31:30

Claims (1)

(57) [Claims] When a preform mat is formed by preforming a reinforcing fiber mat, a recess extending from a portion corresponding to a resin injection port of a molding die to a peripheral portion of a molded product is formed, and the preform mat is formed. A method for molding an FRP molded product, comprising setting the resin in a molding die and injecting a resin from a resin injection port.