JP2571276Y2 - Core material for molding fiber-reinforced resin - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core material such as a foam used for molding a fiber reinforced resin product.

[0002]

2. Description of the Related Art In recent years, FRP (glass fiber reinforced resin) products have been used for various molded products such as outer panels of automobiles. For molding such a fiber-reinforced resin molded product, for example, in the case of an engine hood, a rigid urethane foam is inserted as a core material into the molded product in order to secure the rigidity and strength of the molded product. It is integrally molded. By using the core material in this manner, the weight of the product can be reduced and the surface quality can be improved as compared with the case where the reinforcing fiber such as glass fiber and the resin are used alone.

A conventional FRP engine hood is formed by resin transfer molding (hereinafter referred to as RTM), for example, in the same manner as the molding method described in Japanese Patent Application Laid-Open No. 2-130115. . That is, as shown in FIG. 6, a rib-shaped core material 13 in which a void 14 is partially formed by urethane foam is formed in advance, and this is disposed between the reinforcing glass fiber mats on the front and back sides, and the upper and lower metal members are formed. The FRP layers 11 and 12 are formed around the core material 3 by setting between molds and injecting molten resin such as polyester into the glass fiber for reinforcement by injecting the resin.

In this case, in order to impart rigidity to the engine hood and bend at the time of collision to provide a cushioning effect, the shape of the rib formed on the back side of the product is AA in FIG.
As shown in FIG. 5 which is a cross section of the line and the line BB, the core material 13 is formed by appropriately changing the thickness. Injection of the resin at the time of molding is performed from an injection port of an upper mold for molding the back side 12 of the product. This is because when the resin is injected from above, the resin easily flows into the lower mold for molding the surface 11 of the product, and the trace of the injection port is not left on the surface of the product.

[0005]

However, the glass fiber mat and the core material 13 are pressed by the injection pressure of the resin injected from above.
Moves to the lower mold side, the thickness of the product front side becomes thinner, and conversely, the thickness of the product back side 12 becomes thicker, and it becomes impossible to secure the predetermined thickness on both sides of the FRP layer. Further, when the thickness of the product side is extremely thin, it becomes difficult for the resin to flow at the time of molding, the resin is not sufficiently filled on the surface of the molded product, and a molding defect called a short circuit occurs.

The present invention is intended to improve the quality of a molded product by keeping the thickness distribution of the FRP layer of the molded product within a predetermined range when performing RTM molding using a core material such as a foam material. Aim.

[0007]

According to the present invention, there is provided a core material which is set on a reinforcing fiber mat in a molding die, and a resin is poured into the molding die from above to integrally mold the core material.
A large number of protrusions are formed on the surface of the core material that comes into contact with the reinforcing fiber mat.

[0008]

[Action] When resin is injected from the resin inlet above,
The core material is supported on the fiber mat for reinforcement by the protrusion,
The molten resin flows smoothly through the space of the core material and the fiber mat in this space, and is filled to every corner in the cavity. In this case, since the injected resin flows smoothly and no pressure is applied to the core material when the resin is injected, the distance between the core material and the molding surface of the lower mold is within a predetermined range, and the F on the front side of the product is reduced.
The thickness of the RP layer is formed within a predetermined range.

[0009]

FIG. 1 is a partial sectional view of an engine hood molded product formed using the core material of the present invention, and FIGS. 1A and 1B.
Respectively correspond to the cross section taken along the line AA and the line BB in FIG. 4, and FIG. 2 is a partially enlarged view of the cavity portion during molding.
A glass fiber mat 7 previously formed into a predetermined shape is set on a lower mold 6 for molding the front side of the product, and the core material 3 is provided with a number of projections 4 at a predetermined interval on a side corresponding to the glass fiber mat 7 of the lower mold.
Are formed integrally with a rigid urethane foam, and set together with the glass fiber mat 7 in an upper mold. In the state where the upper and lower dies are clamped, as shown in FIG. 2, the projections 4 of the core material 3 hit the glass fiber mat 7, but the rigid urethane foam has a specific gravity of about 0.2 to 0.4, Because of its light weight, the glass fiber mat 7 does not deform much due to its weight, and is slightly depressed at the portion where the projection 4 hits. 5 are formed, and the glass fibers 7 located in the space 5 are formed.
Has not been crushed at all.

When the resin is injected from the upper resin injection port in the state shown in FIG. 2, the molten resin flows around the core material 3 or from the gap (see 14 in FIG. 6) to the lower surface of the core material 3 and the space 5
And it flows smoothly in the glass fiber mat 7 and is filled to every corner in the cavity. In this case, since the injected resin flows smoothly and no pressure is applied to the core material 3 when the resin is injected, the distance D between the core material 3 and the molding surface of the lower mold 6 is within a predetermined range, and the FRP on the front side of the product is The thickness of the layer 1 is formed within a predetermined range. Projection 4 formed on core material 3
May be arranged so as to optimally control the resin flow in consideration of the position of the injection port and the thickness of each part of the core material. Although the case where the glass fiber mat 7 is formed to have a uniform thickness has been described, a preform mat may be used in which a portion of the core material 3 to which the projection 4 is applied is formed to have a concave shape in advance.

The glass fiber mat set in the lower mold 6 is
As shown in FIG. 3, the layer may be divided into two layers, that is, a layer 7 corresponding to the lower mold 6 and a layer 8 which enters the concave portion of the core material 3, and may be formed in advance. The core material 3 in which the glass fiber mats 7 and 8 thus preliminarily formed in two layers are laminated and the projections 4 are provided thereon.
8 layers of glass fiber mat, the core material 3
Since the glass fiber mat 7 layer is not pressed directly by the core material 3, there is no difference in the density of the glass fiber mats 7, 8, so that the resin flows in the glass fiber mats 7, 8 uniformly. The flow of the resin in narrow places becomes smooth.

[0012]

[Effects of the Invention] The present invention is intended to improve the quality of molded products by keeping the thickness distribution of the FRP layer of the molded products within a predetermined range when molding FRP using a core material such as a foam material. Can be planned.

[Brief description of the drawings]

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

FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3 is a partially enlarged cross-sectional view when a glass fiber mat having a shape different from that of FIG. 2 is used.

FIG. 4 is a rear view of a molded product.

FIG. 5 is a sectional view taken along lines AA and BB in FIG. 4;

FIG. 6 is a plan view showing an example of a core material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Front FRP layer 2 Back FRP layer 3 Core material 3 4 Projection 5 Space part 6 Lower mold 7,8 Glass fiber mat

Claims (1)

(57) [Scope of request for utility model registration] 1. A core material which is set on a reinforcing fiber mat in a molding die, and a resin is injected into the molding die from above to integrally mold the core material. A core material for molding a fiber-reinforced resin, wherein a number of projections are formed on a contact surface.