JPH04257406A - Fiber reinforced resin forming method - Google Patents

Abstract

PURPOSE:To prevent burr and resin rich part from developing in product in the forming of fiber reinforced resin formed article. CONSTITUTION:Reinforcing fiber mats 4 are set in forming molds under the condition that the peripheral edge part of the end of the mats are wrapped round by the fiber mat 5 made of the same material as the mat 4. Thus, the fear of the end of the reinforcing fiber 4 being pinched with molds is eliminated when the molds are closed. Further, since the reinforcing fibers 4 and 5 are densely arranged at the peripheral edge part of a forming part 3 in the reinforcing fiber mats set in the molds, neither burr nor resin rich part develops in a formed product.

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 using reinforcing fibers.

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 order to ensure the rigidity and strength of the molded product, for example in the case of an engine hood, such fiber-reinforced resin molded products are formed by stacking multiple layers of reinforcing fibers such as glass fibers in advance into a mat shape. This glass fiber mat is set in a mold, and molten resin is injected into the mold.

[0003] Japanese Unexamined Patent Application Publication No. 1-253410 describes FRP by resin injection (RI) as described above.
In the molding method, in order to accurately position the reinforced filament to be set in the mold, a clip-shaped filament fixture made of the same elastic material as the reinforced filament is used, and the elasticity of the filament fixture is used to position the reinforced filament in the mold. Press and fix the reinforced filament against the cavity wall,
A method in which molten resin is injected into a mold for molding is described.

0004

[Problem to be solved by the invention] The above-mentioned RI and R
In FRP molding methods such as TM, it is necessary to accurately set the reinforcing glass fibers in the mold so that they do not come out of the molded product. However, during actual molding, the glass fiber mat may be molded shorter than the specified dimensions, or even if it is molded to the specified dimensions, it may not be set accurately in the mold. problem occurs.

[0005] If the pre-formed glass fiber mat is formed shorter than a predetermined size, as shown in FIG. Areas 3a, 3 where the fiber mat 4s is not provided
A is formed, and in a product molded by injecting molten resin in this state, a resin-rich portion is formed at the peripheral edge of the product. In this resin-rich area, there is little or almost no glass fiber, so the strength of the molded product is insufficient and cracks are likely to occur.

In addition, when the glass fiber mat is molded to a length longer than a predetermined size, the upper mold 1 as shown in FIG.
When the lower mold 2 is closed, the glass fibers 4c, 4c on the periphery of the cavity are forced and come into close contact with the periphery of the cavity, and in some cases may be caught in the gap between the upper mold 1 and the lower mold 2, causing the mold to close. The mold does not close completely, and a gap t remains between the upper mold 1 and the lower mold 2, resulting in large burrs on the product.

[0007] In the FRP molding method using RI described in the above-mentioned Japanese Patent Application Laid-open No. 1-253410, it is possible to use a filament fixture when the molded product has a simple shape and is large, but the engine frame In the case of panel products such as boards and doors, the thickness of the molded product is 2.5 to 3.0 m.
Since it is very thin (m), it is difficult to manufacture the fixture, which increases the cost, and also makes it difficult to set the fixture. Also,
Because the adhesion between the fixture and the injected resin will be insufficient,
There is a risk that the strength of the product will be degraded, and furthermore, a portion of the fixing device will be exposed to the surface of the molded product, resulting in surface quality problems.

The purpose of the present invention is to solve the above-mentioned problems and provide a molding method that facilitates the setting of reinforcing fibers even in the molding of thin panels and maintains good quality of fiber-reinforced resin molded products. It is something to do.

[0009]

[Means for Solving the Problems] The present invention provides for forming the end peripheral edge of a fiber mat, in which reinforcing fibers are preformed into a predetermined shape, into a U-shaped cross section using fibers of the same quality as the reinforcing fibers. Either wrap the reinforcing fibers in a plastic mat and set it in a mold, or wrap the reinforcing fibers on the product surface side in a predetermined shape so that the reinforcing fibers wrap around the terminal edges of the other reinforcing fibers. This is a fiber-reinforced resin molding method that involves pre-molding a material, setting it in a molding mold, and injecting molten resin into the mold.

0010

[Operation] The reinforcing fiber mat set in the mold is wrapped around its terminal edge with a fiber mat of the same quality.
There is no risk of the ends of the reinforcing fibers being caught in the mold when the mold is closed, and the reinforcing fiber mat set in the molding mold has reinforcing fibers densely arranged around the periphery of the molding part. As a result, resin-rich areas do not occur in the molded product.

[0011]

[Example] Fig. 1 (A
), the lower mold 2 is a cavity mold for molding the outer surface of the engine hood molded product, the upper mold 1 is a core mold for molding the back surface of the engine hood molded product, and the cavity 3 of the lower mold 2 is A plurality of preformed glass fiber mats 4 are set. In this case, a band-shaped auxiliary mat 5 as shown in FIG. 1B, which is preformed from glass fiber and has a U-shaped cross section, is set by wrapping the peripheral edge of the end of the glass fiber mat 4.

When the glass fiber mat 4 wrapped with the auxiliary mat 5 shown in FIG. 1 is set, the glass fiber content in the end portion of the molded product is greatly increased. In order to make the glass fiber content of the molded product uniform, as shown in FIG. The glass fiber mat 4 wrapped with the auxiliary mat 5 is set in the same manner as shown in FIG. In FIG. 2, when molten resin is injected into the mold from the resin injection hole 6 of the upper mold 1, the molten resin flows into the glass fiber mat 4 and the auxiliary mat 5.
It penetrates into the inside and covers their surfaces, molding them into one piece. In this case, the thickness of the end portion of the molded product is increased, but since the overhanging portion is on the back side of the molded product, not only does this not cause any problem as a product, but the strength of the end portion of the product is increased.

Next, another molding method will be explained. The portion 5a of the auxiliary mat 5 on the molding surface side of the lower mold 2 shown in FIG. 1 has a high glass fiber content and protrudes, so there is a possibility that glass fibers will appear on the surface of the molded product after molding. . The outermost glass fiber mat 4a, which will be the surface side of the molded product, is cut in advance to be shorter than the other glass fiber mats 4 to be wrapped with the auxiliary mat 5, and the auxiliary mat 5 is used to terminate the mat as shown in FIG. 3(A). The glass fiber mat 4 that wraps around the periphery of the mat 4 is placed on top of the mat 4. Alternatively, as shown in FIG. 3(B), the upper mold 1 having the recessed portion 7 shown in FIG. 2 may be used and set in the same manner. This molding method eliminates the risk of glass fibers appearing on the surface of the product after molding.

Next, yet another molding method will be explained with reference to FIG. In this forming method, without using the auxiliary mat 5, at the time of preforming the glass fiber mat 4, the outermost layer glass fiber mat 4b is bent into an L-shape at the end thereof to wrap the inner layer glass fiber mat 4. It is preformed in one piece, and then set in a mold and molded.

[0015]

Effects of the Invention The present invention effectively prevents the formation of burrs and resin-rich layers on molded products due to the glass fiber mat being caught in the mold, and also prevents the glass fiber mat from being caught in the mold. Setting is easy, and
Good surface quality of the product can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of an embodiment of the present invention and a perspective view of an auxiliary mat.

FIG. 2 is a cross-sectional view of another embodiment of the invention.

FIG. 3 is a cross-sectional view of another embodiment of the invention.

FIG. 4 is a cross-sectional view of yet another embodiment of the invention.

FIG. 5 is an explanatory diagram of a conventional molding method.

FIG. 6 is an explanatory diagram of a conventional molding method.

[Explanation of symbols]

1 Upper mold
2 Lower mold 3 Cavity
4 Glass fiber mat 5 Auxiliary mat
6 Resin injection hole 7 Recess

Claims (2)

[Claims] Claim 1: The terminal edge of a fiber mat in which reinforcing fibers have been preformed into a predetermined shape is wrapped with an auxiliary mat made of fibers of the same quality as the reinforcing fibers and preformed into a U-shaped cross section. A fiber reinforced resin molding method characterized by setting the resin in a mold and injecting molten resin into the mold. 2. A fiber mat is preformed in advance into a predetermined shape so that the reinforcing fibers on the product surface side among the plurality of reinforcing fibers wrap the peripheral edges of the other reinforcing fibers, and the fiber mat is formed. A fiber reinforced resin molding method characterized by setting the resin in a mold and injecting molten resin into the mold.