JP3259361B2 - 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 molding die, injecting a resin and injecting a resin with a rib.
The present invention relates to a method for forming an RP 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 FRP (fiber reinforced resin) molded product by injecting a resin into a mold. When an engine hood of an automobile is formed by FRP by this RTM method, it is necessary to integrally form a rib on the back surface of the engine hood for reinforcement. Conventionally,
In the integral molding of the rib, it is common to insert a core material into a molding portion of the rib and mold the rib. FIG. 2 shows the back surface of a conventional FRP engine hood.
FIG. 3 shows an X-ray cross section. In this FRP engine hood W, a core material 4 such as a foam is disposed between two glass fiber mats 1 and 3 to form a rib that rises to the back side,
The product has synthetic resin layers 5 and 6 formed on the front and back of the product. The molding of the FRP engine hood W by RTM is performed by preparing a convex mold that is usually an upper mold and a concave mold that is usually a lower mold, cleaning the molded portions of both molds, applying a release agent, and then ,
Spray gun or the like is used to spray a gel coat onto the concave molding part (the front molding part of the product) to set a glass fiber preform mat and a core material for forming ribs in the mold as a reinforcing material of the product. The molds are closed and mold-clamped, the molten resin is injected from the injection port of the upper mold, the resin is completely cured, 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 according to the product shape is used, and the core material is also preformed to a shape conforming to the rib shape. Used. RTM above
In the molding, the curing of the molten resin in the portion in contact with the core material 4 during molding is delayed, and when the resin in this portion contracts, the product is warped or the surface of the product has sink marks. In particular, if sinks occur in the resin layer 5 on the front side of the product, the product becomes defective. Japanese Patent Application Laid-Open No. 1-163016 discloses that the resin on the surface of a product is formed by laying a shrink-prevention sheet of closed cells over the entire width of a core material forming a rib portion on a front side of the product and injecting the resin. A method for producing an FRP molded product by a resin injection method (RI) in which sink is prevented from occurring in a layer is described.

[0004]

In the above-mentioned conventional RTM, a core material 4 for forming ribs is additionally required in addition to the glass fiber preform mats 1 and 3, and the core material 4 is used as a mold. It is difficult to position and set inside, and productivity is poor. Furthermore, the insertion of the core material causes a product defect due to sink and warpage. The molding method described in the above-mentioned publication also requires a core material for forming ribs, and it is difficult to position and set the core material in a mold. Even if this can be prevented, it is necessary to lay the anti-sink sheet over the entire width of the core material forming the rib portion, which inevitably increases the cost.

According to the present invention, a rib shape is formed by a plurality of glass fiber mats, and when each glass fiber mat is preformed, the thickness of a rib portion of the preform mat is changed to thereby form the preform mat. The purpose of the present invention is to provide an FRP molding method in which a reinforcing rib can be formed on a molded product without using a core material, and the product is free from sink marks and warpage simply by setting a combination in a normal molding die. And

[0006]

SUMMARY OF THE INVENTION The present invention relates to a glass fiber preform mat in which the surface on the front side of a product is formed smoothly, and a preform in which a rib-shaped portion of the glass fiber mat which is an intermediate layer of the product is compression-molded. and the mat, the rib-shaped portion of the glass fiber mat as the back side of the product, an intermediate of the product
Glass fiber mats with the same basis weight as the glass fiber mat
When using the unit, the rib-shaped part of the intermediate layer of the product
This is a method of molding an FRP molded product in which a preform mat compression- molded to about half the molding thickness is combined, the combined preform mat is set in a molding die, and a resin is injected from a resin injection port.

[0007]

[Function] When the preform mat is set in the molding die and the molten resin is injected, the rib portion of the combined preform mat is hardly molded because the preform mat on the back side which covers the preform mat of the intermediate layer is hard. The ribs of the preform mat are not deformed by the injection pressure,
Since the material to be inserted into the mold is the same material as the glass fiber mat only, the molten resin flows uniformly in the mold and penetrates into the glass fiber, preventing the molded product from warping and preventing sink on the product surface. it can.

[0008]

FIG. 1 shows a partial cross section of a combined preform mat preformed with a glass fiber mat, which is inserted into a mold. This preform mat is a combination of preform mats obtained by preforming three glass fiber mats, and a rib portion is preformed on the preform mat 1 on the back side of the product. During this molding, the rib portion 1a is strongly compressed to be molded hard.
Although the rib portion is also formed on the preform mat 2 of the intermediate layer, the rib portion 2a is preformed thicker without being compressed too much. The preform mat 3 on the front side of the product is preformed smoothly in a shape corresponding to the product shape. Combine the three preform mats 1, 2, 3 as shown in FIG.
This is set in a normal mold and FTM is performed by RTM or RI.
Form the RP.

When this preform mat is set in a molding die and molten resin is injected, the resin penetrates into the glass fibers of each of the preform mats 1, 2, and 3, and the glass fiber mat and the molding surface of the molding die are in contact with each other. And a resin layer is formed on the front and back of the glass fiber mat. At this time, since the preform mat 2a of the intermediate layer is formed to be thick and has a large volume, and the preform mat 1a covering the rib portion is formed hard, the rib portion of the preform mat is formed by the resin injection pressure. The ribs are not deformed, and the material to be inserted into the mold is the same material as the glass fiber mat only, so the molten resin flows uniformly in the mold and penetrates into the glass fiber, and the molded product No warpage occurs and sinks on the product surface can be prevented.

When a glass fiber mat having a basis weight of 450 g / m ² is used, the rib portion 1 a of the preform mat 1 on the back side of the product has a moderate hardness when compressed to about 0.5 to 0.6 mm. When a glass fiber mat having a basis weight of 450 g / m ² is used, the rib portion 2 a of the preform mat 2 of the layer is preferably compression-molded to about 0.8 to 1.2 mm. Since the rib portion is formed of a glass fiber mat, the width D of the rib portion is about 3 to 4 mm, and the height H of the rib portion is H.
Is limited to 10 to 15 mm in relation to the elongation of the glass fiber mat.

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.

[0012]

According to the present invention, when a rib shape is preformed with a plurality of glass fiber mats, the molding thickness of the rib portion of each preform mat is changed, and when the preform mats are combined, the rib portion is formed. Since a predetermined rigidity and volume can be given to the mold, the ribs are not deformed by the resin injection pressure when the preform mat is set in the mold and the resin is injected. Since ribs for reinforcement can be formed on molded products without performing
P can be obtained at low cost. Moreover, there is no danger of sink marks and warpage occurring in the product, and defective molding can be prevented.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a preform mat used in the present invention.

FIG. 2 is a rear view of the product.

FIG. 3 is a partially enlarged view of line XX in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Back side preform mat 1a Rib part 2 Intermediate preform mat 2a Rib part 3 Front side preform mat 4 Core material

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Claims (1)

(57) [Claims] 1. A glass fiber preform mat in which the surface on the front side of a product is formed into a smooth shape, a preform mat in which a rib-shaped portion of the glass fiber mat as an intermediate layer of the product is compression-molded, and a back side of the product. The glass fiber mat which becomes the intermediate layer of the product
When using a glass fiber mat with the same basis weight as above
About half the molded thickness of the rib-shaped part of the intermediate layer of the product
A method for molding an FRP molded product, comprising: combining a preform mat which has been compression- molded into a mold; setting the combined preform mat in a molding die; and injecting a resin through a resin injection port.