JPH04246510A - Forming method of fiber reinforced resin formed body - Google Patents

Abstract

PURPOSE:To eliminate the trouble, which may occur when foaming urethane is used as core material, in the forming of a fiber reinforced resin formed body. CONSTITUTION:Reinforcing glass fiber mats 1 and 2, between which an elastic bag 3 is arranged, are set in molds. Air having the pressure, which is higher than the pressure of resin to be poured, is forced in the elastic bag 3. Next, molten resin is poured in the reinforcing glass fiber mats. After the hardening of the resin, the molds are opened so as to demold a formed article, within which the hollow elastic bag is left as its shape is kept.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding fiber-reinforced resin products.

0002

2. Description of the Related Art Recently, FRP (glass fiber reinforced resin) products have come to be used for various molded products such as automobile outer panels. In the case of the engine hood shown in FIG. 3, for example, the molding of such a fiber-reinforced resin molded product requires the rigidity of the molded product,
In order to ensure strength, etc., foamed urethane or the like is inserted as a core material 10 into the molded product and integrally molded, as shown in FIG. 2, which is a cross-sectional view taken along the line X-X in FIG. By using a foamed material or the like in this manner, the weight of the product can be reduced and the surface quality can be improved compared to when molding is performed using only reinforcing fibers such as glass fibers and resin.

[0003] Conventional molding of FRP engine hoods is similar to the molding method described in, for example, Japanese Patent Laid-Open No. 2-130115. The FRP layer is placed around the core material 10 by injecting a resin such as polyester, impregnating the reinforcing glass fiber mats 1 and 2 with the resin, and hardening the resin. It is formed by coating.

[0004] Furthermore, in Japanese Patent Application Laid-open No. 61-207612, reinforcing material and FRP material are put into the cavity of the mold,
By inflating a pressurized bag within the cavity, F
A method for manufacturing an FRP helmet has been proposed in which RP material is distributed between the inner surface of a mold cavity and a pressurized bag.

[0005]

[Problems to be Solved by the Invention] However, when an engine hood is heated to 120°C in the next painting process, the uncured portion of the urethane foam that is the core material inside the engine hood reacts and gas is released, stress is generated inside the FRP molded body, and distortion, sink marks, etc. occur in the product. The above problems can be solved if there is a highly heat-resistant foam material, but the improvement in the heat resistance of the foam material itself is close to its limit, and the highly heat-resistant foam material is expensive.

[0006] The method for manufacturing an FRP helmet described in the above-mentioned Japanese Unexamined Patent Publication No. 61-207612 includes placing a reinforcing material and an FRP material in a cavity of a mold in advance, setting a pressure bag inside the mold, and FR by expanding the pressurized bag
The P material is filled around the reinforcing material, and the pressurized bag is released from the mold by shrinking under pressure after molding the helmet. That is, the pressurized bag does not remain in the molded article in place of the core material.

[0007] The present invention provides a molded product with a shape (
It is an object of the present invention to provide a method for molding a fiber-reinforced resin molded article that can impart a shape with a section modulus that increases rigidity.

[0008]

[Means for Solving the Problems] The present invention provides an elastic bag arranged between reinforcing glass fiber mats, set in a mold, and pressurized air into the elastic bag at a pressure higher than the pressure of the injected resin. This is a method of molding a fiber-reinforced resin molded article, in which a reinforcing glass fiber mat is pressed against a molding surface of a mold, and then a molten resin is injected into the reinforcing glass fiber mat.

[0009]

[Operation] When compressed air is supplied to inflate the elastic bag, the glass fiber mat set around the elastic bag is pressed against the molding surfaces of the upper and lower molds, making it hollow. When molten resin is injected in this state, the resin is impregnated into the glass fiber mat while the elastic bag maintains its hollow shape, and the FRP layer is integrally coated and formed on the outer surface of the hollow elastic bag. After the resin has hardened, the mold is opened and removed, leaving the hollow elastic bag as a cavity while maintaining its shape.

0010

[Example] In FIG. 1 showing a mold in a molding state, a glass fiber mat 1 for molding the outer surface of an engine hood molded product is shown.
An elastic bag 3 made of neoprene rubber, silicone rubber, etc. is placed between the glass fiber mat 2 for the back side of the engine hood and
A medium inlet pipe 7 and a medium outlet pipe 8 installed in the lower die 6 are connected to the elastic bag 3. A coupler 13 with a check valve is installed in the medium inlet pipe 7 and the medium outlet pipe 8. A resin injection port 5 is provided in the upper mold 4, and temperature control circuits 9, 9 are provided in the upper mold 4 and the lower mold 6. Pump 11 and temperature controller 1
2 is a temperature control device that is attached to and detached from the coupler 13 with a check valve.

Next, the molding of the fiber-reinforced resin molded product will be explained. Compressed air is supplied from the medium introduction pipe 7 to inflate the elastic bag 3 with an air pressure higher than the resin injection pressure, and the glass fiber mats 1 and 2 set around the elastic bag 3 are placed on the molding surfaces of the upper mold 4 and the lower mold 6. Press to bring it into the state shown in Figure 1. When molten resin is injected from the resin injection port 5, the glass fiber mats 1 and 2 are impregnated with the resin while the elastic bag 3 maintains its hollow shape, and the outer surface of the hollow elastic bag 3 is integrally covered with an FRP layer. Ru. Therefore, after the resin has hardened, the molded product is opened and removed, and the hollow elastic bag 3 remains as a cavity while maintaining its shape.

When using thermoplastic resin, the upper and lower molds, the glass fiber mats 1 and 2, and the elastic bag 3 must be heated.
The flow of the injected resin within the mold is obstructed. Upper mold 4 and lower mold 6
In addition to the temperature control circuits 9, 9 installed in the pump 1.
1 and a temperature regulator 12 is connected to a coupler 13 with a check valve, a medium heated by water or oil through the temperature regulator 12 by a pump 11 is circulated within the elastic bag 3, and a glass fiber mat is heated. After heating 1, 2 and elastic bag 3 in advance,
By switching to the supply of compressed air, the flow of the injected resin becomes smooth, making it possible to manufacture FRP with a thin surface layer. Moreover, if the temperature regulator 12 is switched to cooling after filling with resin, it becomes possible to control the hardening time of the resin.

[0013] The material of the elastic bag may be any other material as long as it is an elastic material that is not corroded by the solvent of the injected resin and can withstand the temperature of the injected resin. It can also be applied to the molding of architectural structures other than automobile parts such as engine hoods and outer panels.

[0014]

Effects of the Invention According to the present invention, a molded product can be molded into a hollow shape with a cross-section coefficient that increases rigidity without using a foam core, so a molded product that is lightweight and has high heat resistance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line XX in FIG. 3;

FIG. 3 is a perspective view of the engine hood.

[Explanation of symbols]

1, 2 Reinforcing fiber mat 3 Elastic bag 4 Upper mold 5 Resin injection port 6 Lower mold 7 Media introduction pipe 8 Media outlet pipe

Claims (1)

[Claims] Claim 1: An elastic bag is arranged between reinforcing glass fiber mats and set in a mold, and air is injected into the elastic bags at a pressure higher than the pressure of the injected resin, thereby molding the reinforcing glass fiber mat into the mold. A method for molding a fiber-reinforced resin molded article, which comprises pressing a molding surface and then injecting a molten resin into a reinforcing glass fiber mat.