JPH0712643B2 - Method for producing fiber-reinforced composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a fiber reinforced composite material that is used for a structure such as a space structure such as an artificial satellite, OA equipment, automobiles and leisure goods to reduce vibration and noise. The present invention relates to a method for manufacturing a material.

(Prior Art) A fiber-reinforced composite material such as CFRP is obtained by solidifying an inorganic fiber such as carbon or glass fiber or an organic fiber such as aramid fiber with a resin such as an epoxy resin, a polyimide resin, or a polyetheretherketone resin. Is.

The fiber-reinforced composite material is lighter and has higher strength than conventional metal-based structural materials, and is excellent in that desired mechanical properties can be realized by controlling the fiber orientation angle. For this reason, it has come to be widely used for structural materials such as space structures, aircraft, automobiles, and leisure goods, which require strong and light weight.

(Problems to be Solved by the Invention) With the expansion of applications of structures manufactured from this type of composite material, vibration of the structures has become a problem.

Fiber-reinforced composite materials are lightweight and have small vibration damping characteristics (loss factor η = 0.001 ~
Because of 0.01), vibration is likely to occur. In addition, the structure is often integrally formed, and unlike conventional metal structural materials, vibration damping (structural damping) due to friction at the connecting portion cannot be expected. For this reason, in space structures such as artificial satellites, vibrations of the structures cause failure of on-board equipment and deterioration of antenna position accuracy. Therefore, increasing the vibration damping characteristics of the fiber-reinforced composite material has become an important issue.

For the purpose of solving these problems, a method of increasing the vibration damping of the matrix resin by increasing the vibration damping of the matrix resin has been studied. This is a method in which a flexibility-imparting agent such as polyethylene glycol, polypropylene glycol, or liquid rubber is added to a matrix resin, and a composite material is produced using a resin having increased vibration damping characteristics.
However, although the addition of the flexibility-imparting agent can improve the vibration damping characteristics of the resin by several tens of times, the vibration damping characteristics of the composite material can only be increased by several times, and the rigidity will be greatly reduced, which is an effect. Not at all. The present invention solves the above problems, and an object of the present invention is to provide a fiber-reinforced composite material having large vibration damping characteristics.

(Means for Solving the Problem) The present invention is characterized in that a sheet molding compound made of a reinforcing resin such as carbon or glass fiber and a matrix resin and a viscoelastic material sheet are laminated and cured by heating under pressure. It is to provide a method for producing a fiber-reinforced composite material.

(Operation) In the production method of the present invention, since the sheet molding compound composed of the resin and the reinforcing fiber is laminated and cured with the viscoelastic material sheet, the composite material layer composed of the reinforcing fiber such as carbon or glass fiber and the resin and the viscoelastic layer. It is possible to realize a fiber-reinforced composite material that is laminated and integrated. The composite material has large vibration damping characteristics due to the vibration damping effect of the viscoelastic material between the layers.

As a viscoelastic material sheet, a semi-cured product (B stage shape)
Further, known materials such as a cured product sheet, a thermoplastic elastomer sheet such as polyolefin or polyether, and a silicone rubber sheet can be used.

(Example) Below, the Example of this invention is described by figures. FIG. 1 shows a flow of the method for producing the fiber-reinforced composite material of the present invention. In the example, the sheet molding compound is cut according to the mold, and the viscoelastic material sheet and the sheet molding compound are laminated in the mold according to the required laminating order. The laminate is molded and cured by pressing and heating with an autoclave or a press.

FIG. 2 shows a cross-sectional view of a composite material manufactured by using the manufacturing method of the embodiment shown in FIG. The sheet molding compound 2 used was made of short glass fibers and polyester resin. As the viscoelastic material sheet 1, a polyolefin sheet having thermal adhesiveness was used. As is clear from the figure, it has a structure in which a composite material layer made of short glass fibers and a polyester resin and a polyolefin sheet are laminated and integrated.

FIG. 3 shows the relationship between the loss coefficient and the frequency of the composite material of the embodiment shown in FIG. Bending vibration was applied to the composite material test piece for measurement. In the figure, the solid line is the characteristic of the composite material of the example of FIG. 2, and the broken line is the characteristic of the fiber reinforced composite material produced by the conventional production method. In each case, the loss coefficient was obtained from the free damping curve at the natural frequency. As is clear from the figure, the composite material produced by the manufacturing method of the present invention has a larger vibration damping characteristic than the conventional one.

(Effects of the Invention) As described above, according to the present invention, it becomes possible to realize a fiber-reinforced composite material having a large vibration damping characteristic, and it is possible to reduce a failure of a mounted device in a space structure such as an artificial satellite or a positional accuracy of an antenna. It has the effect of being able to solve the problems of noise and noise from automobiles.

[Brief description of drawings]

FIG. 1 is a flow chart of a manufacturing method of an embodiment of the present invention, FIG. 2 is a cross-sectional view of a composite material manufactured by using the manufacturing method of the embodiment, and FIG. 3 is a diagram showing a loss coefficient of the composite material. . 1 …… Viscoelastic material sheet, 2 …… Sheet molding compound

Claims (1)

[Claims] 1. A method for producing a fiber-reinforced composite material, which comprises laminating a sheet molding compound comprising a reinforcing fiber and a matrix resin and a viscoelastic material sheet, and curing the laminated sheet by pressurizing and heating.