JPH02215510A - Manufacture of fiberglass reinforced resin structural body - Google Patents

Abstract

PURPOSE:To obtain a fiberglass reinforced resin structural body into which resin is infiltrated completely, by a method wherein the resin is kept infiltrated into apart whose fiber content is high or a fiber of a fibrous state part, into which the resin is hard to infiltrate, prior to casting of the resin into a mold. CONSTITUTION:Resin is kept infiltrated into a part, whose fiber content is high, or a fiber of a fibrous state part, into which resin is hard to infiltrate, prior to casting of the resin into a mold. It is better to make use of the same series matter with resin cast later on as the resin to be used for infiltration beforehand and a matter, which is in a state of a prepreg, may be used. Thermosetting resin, for example, unsaturated polyester or epoxy or vinyl can be used. Thermosetting resin, for example, unsaturated polyester or epoxy or vinyl can be used. The infiltration of the resin which is infiltrated into a fiber body beforehand can be performed, for example, into a resin bath. It is preferable that the fiber body into which the resin is infiltrated is kept under the state of the prepreg. In this instant, when the same is hardened completely, the resin becomes hard to run after a complicated form of a mold surface at the time of setting and it is not preferable since adhesion to the resin cast later on becomes worse.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a fiber-reinforced resin structure.

(Prior Art) Fiber-reinforced resin structures are attracting attention as materials for parts such as vehicle structures that require properties such as light weight, high strength, and high rigidity.

In order to obtain lightweight, high-strength, and high-rigidity products in fiber-reinforced resin structures, it is possible to increase the fiber content by using long fibers oriented in the same direction as reinforcing fibers, by increasing the fiber content, etc. It is necessary to increase the rate (Vf value). Therefore, fiber-reinforced resin structures including layers with high Vf values have been proposed. Such a fiber reinforced resin structure having a plurality of fiber layers having different Vf values is, for example,
This method has been proposed in Utility Model Application No. 17403/1980, Japanese Patent Application No. 86217/1982, and Japanese Patent Application No. 14478/1983.

The above-mentioned fiber-reinforced resin structures are usually produced by setting a dry fiber base material in a mold and injecting the resin using the resin-in-die excin method, cold press method, SRIM method, etc. It is molded by impregnating it into a fiber base material and curing it.

(Problems to be Solved by the Invention) However, according to the above molding method, in areas with a high Vf value, that is, areas with a large fiber content or areas where long fibers are used, the flow resistance of the fibers to the resin is low. Due to the high temperature, there is a problem that the resin is not sufficiently impregnated into the fiber base material.

In addition, when manufacturing a fiber-reinforced resin structure that includes both high and low Vf values, the resin flows to the low Vf values avoiding the high Vf values, so the high Vf values The resin impregnation rate becomes significantly lower.

For example, in the vehicle rocker part 6 manufactured by the conventional method shown in the cross-sectional view of FIG.
The resin is well impregnated due to the low Vf value, but
Layer 8 containing long fibers has a high Vf value and is not sufficiently impregnated with resin.

FIG. 4 is a sectional view showing the manufacturing process of a fiber-reinforced resin structure in which a layer 10 of long fibers is partially arranged between layers 9, 9 of short fibers. Upper mold 11 and lower mold 12
When resin is injected in the direction of arrow A with short fibers and long fibers set between the
Since the resin flows through the layer 9 of short fibers having a low Vf value while avoiding this, the layer 10 of long fibers is not sufficiently impregnated with the resin. In particular, when the flow direction of the resin is perpendicular to the fiber direction as shown in the diagram, the flow resistance becomes significantly high.

FIG. 5 is a sectional view showing the manufacturing process of a fiber-reinforced resin structure having a portion 14 including three layers and a portion 15 including four layers of fiber preforms 13 in which short fibers are randomly oriented. As shown in the diagram, 3N or 4 layers of the above fiber preform are set between the upper mold 16 and the lower mold 17, and the arrow B
When the resin is injected in the direction of , the resin flows avoiding the part containing four layers of fiber preforms with a high Vf value, and therefore the fibers in this part are not sufficiently impregnated with the resin.

As mentioned above, in the conventional manufacturing method of a fiber-reinforced resin structure having a portion with a high Vf value, the resin is not sufficiently impregnated into the portion with a high Vf value, and the molded product obtained thereby has the following effects: There were problems such as peeling in the unimpregnated areas of the resin. Therefore, the present invention aims to provide a method for manufacturing a fiber-reinforced resin structure having a layer with a high Vf value, in which the fibers of the layer with a high Vf value are also satisfactorily impregnated with resin. purpose.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a molding method in which a resin is injected into a mold, and a portion with a high fiber content or a fiber shaped portion that is difficult to impregnate with resin is provided. A method for manufacturing a fiber-reinforced resin structure having a method of manufacturing a fiber-reinforced resin structure, characterized in that before injecting the resin into a mold, fibers in a portion with a high fiber content or a fiber form portion that is difficult to be impregnated with resin are impregnated with a resin. The present invention relates to a method for manufacturing a fiber-reinforced resin structure.

The part with a high fiber content (Vf value) refers to a method of increasing the fiber content, for example, a method of increasing the number of laminated preforms to be set, or a method of laminating long fibers oriented in the same direction. It means a part that is formed and has a Vf value higher than that of a commonly used fiber-reinforced resin.

Examples of fiber forms that are difficult to impregnate with resin include continuous fibers.

Although the method of the present invention is more effective in producing a fiber-reinforced resin structure in which a portion with a high Vf value and a portion with a low Vf value are combined, the method of the present invention is more effective in manufacturing a fiber-reinforced resin structure with a high Vf value as a whole. It can also be applied to the production of

The resin used for pre-impregnation should be of the same type as the resin that will be injected later, and may be in a prepreg state (semi-cured state).For example, unsaturated polyester Thermosetting resins such as epoxy, vinyl ester, etc. can be used.

A curing agent or an accelerator can be added to the pre-impregnated resin according to a conventional method. The amount of these additives to be added is preferably adjusted so that the timing of curing of the resin injected later and the resin impregnated in advance are almost the same at the mold temperature.

Impregnation of the fiber body with the pre-impregnated resin can be carried out, for example, in a resin bath. The resin-impregnated fibrous body undergoes a certain amount of reaction to make it easier to handle, and it becomes semi-hardened!
! (prepreg state) is preferable. At this time, if it is completely cured, it will be difficult to conform to the complex shape of the mold surface during setting, and the adhesion with the resin that will be injected later will be poor, which is not preferable.

Fibers set in the mold without being pre-impregnated with resin, i.e. Vf
It is preferable that the fibers in the lower value portion are set in a mold in the form of a preform.

The method of the present invention can be applied to any method for manufacturing fiber-reinforced resin in which fibers are set in a mold and resin is injected, such as a resin injection method, a cold press method, and a SRIM method.

(Function) In the method for producing a fiber reinforced resin structure of the present invention, before pouring the resin into a mold, fibers in areas with a high Vf value or in fiber form areas that are difficult to impregnate with resin are impregnated with resin. It is possible to produce a fiber-reinforced resin structure in which fibers are completely impregnated with resin, even in areas with high fibers and in fiber-shaped portions that are difficult to impregnate with resin.

(Example) A rocker portion 2 of a vehicle floor 1 having the shape shown in FIG. 1 is manufactured by the method of the present invention.

As shown in FIG. 2, a part of the rocker has a dry short fiber preform 3 arranged around a rectangular parallelepiped foam 5,
A continuous fiber body 4 pre-impregnated with resin is arranged above and below the continuous fiber body 4, and a material with a dry short fiber preform 3 arranged around it is set in a mold, and then resin is injected,
Manufactured by curing.

Impregnation of the continuous fiber body with resin is performed by immersing the continuous fiber body in a resin containing an appropriate amount of curing agent and additives in a resin bath. is used after being cured into a prepreg state.

Test example: A fiber-reinforced resin structure containing a continuous fiber portion and a short fiber portion at a fiber ratio of 1:1 and having an average Vf value of 50% was manufactured by the same method as in the above example. In addition, a fiber-reinforced resin structure with a Vf value of 28% was manufactured using the same method as the manufacturing method of the actual product except that the continuous fiber body was not impregnated with resin in advance. Comparative Product 1), Comparative Product 1 A fiber-reinforced resin structure with a Vf value of 50% was manufactured in the same manner as (comparative separate product 2). A test piece was cut out from each fiber-reinforced resin structure, and the impregnation rate and elastic modulus ratio of the resin were examined. Ta. The resin impregnation rate is calculated by the following formula by determining the theoretical resin amount determined from the weight of the molded product and the actual impregnated resin amount.

The elastic modulus ratio is determined by setting the elastic modulus of comparative product 1 to 1.0.

The results are shown in Table 1 below.

Table 1 From Table 1, Comparative Example 2, which has a high Vf value, includes a region that is not impregnated with resin (resin impregnation rate = 55%) and could not obtain an elastic modulus worthy of evaluation. The resin impregnation rate of the product with the same Vf value (50%) as product 2 is 100%.
Met. Further, it can be seen that the elastic modulus of the practical product is much higher than that of comparative product 1, which has a low Vf value.

(Effects of the Invention) In the method for producing a fiber reinforced resin structure of the present invention, the fibers in the portions with a high Vf value or in the fiber form portion are impregnated with the resin in advance. It is possible to obtain a product completely impregnated with resin.Therefore, it is possible to obtain a lightweight, high-rigidity, and high-strength product.Furthermore, although the resin viscosity increases with time, in the method of the present invention,
Since it is only necessary to pour the resin into areas with a low Vf value where the resin is satisfactorily impregnated, the resin can be poured more quickly to areas farther away, making it possible to integrally mold large parts. Furthermore, the number of resin injection ports can be reduced and the mold structure can be made simple, so mold costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a vehicle floor manufactured by an embodiment of the present invention, FIG. 2 is a perspective view showing a part of the locker of the vehicle floor in FIG. 1, and FIG. Sectional view showing a part of the rocker manufactured by the structure manufacturing method, No. 4
FIG. 5 is a cross-sectional view of a mold for explaining a conventional method for manufacturing a fiber-reinforced resin structure. Vehicle floor 1

Claims (1)

[Claims] In a method of manufacturing a fiber-reinforced resin structure having a portion with a high fiber content or a fiber-shaped portion that is difficult to impregnate with resin, the resin is injected into the mold before the resin is injected into the mold. A method for producing a fiber-reinforced resin structure, which comprises impregnating fibers with a resin in portions with a high content rate or portions in fiber form that are difficult to impregnate with resin.