JPH03120036A - Manufacture of fiber-reinforced composite material - Google Patents

Abstract

PURPOSE:To obtain large vibration attenuating characteristic by laminating resin-immersed sheet or matlike reinforcing fiber and viscoelastic material in a mold, and curing it. CONSTITUTION:A sheet or mat-shaped reinforcing material is laid and aligned in a mold of a desired shape, laminated while immersing with matrix resin. When the laminate reaches a suitable thickness, a viscoelastic material is provided partly or on the whole surface of the reinforcing material, the reinforcing material is then again laid and aligned, and laminated while immersing with matrix resin. This steps are repeated, cured, removed from the mold, and shaped. Here, as the matrix resin, epoxy resin (uncured state) mixed with amine curing agent is used. As the viscoelastic material, a polyolefin sheet 2 is employed. A CFRP layer 1 made of carbon fiber and epoxy resin and the sheet 2 have a laminated integral structure. Thus, large vibration attenuating characteristic is obtained.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to space structures such as artificial satellites, OA equipment, automobiles, etc.
The present invention relates to a method for producing a fiber-reinforced composite material that can be used in structures such as leisure goods to reduce vibration and noise.

(Prior technology) Fiber-reinforced composite materials such as CFRP are made by solidifying inorganic fibers such as carbon and glass fibers or organic fibers such as aramid fibers with resins such as epoxy resin, polyimide resin, and polyether ether ketone resin. It is something.

Fiber-reinforced composite materials are superior in that they are lighter and stronger than conventional metal-based structural materials, and desired mechanical properties can be achieved by controlling the fiber orientation angle. For this reason, it has come to be widely used as a structural material for space structures, aircraft, automobile leisure goods, etc., which strongly require weight reduction.

(Problems to be Solved by the Invention) As the uses of structures made of this type of composite material expand, vibration of the structures has become a problem.

Fiber-reinforced composite materials are lightweight and have low vibration damping properties (loss coefficient rl = 0.0) comparable to conventional metal structural materials.
01 to 0.01), vibrations are likely to occur. Also,
Structures are often manufactured by integral molding, and unlike conventional metal structural materials, vibration damping (structural damping) due to friction at connections cannot be expected. For this reason, in space structures such as artificial satellites, vibrations of the structure cause failures of onboard equipment and a decrease in antenna position accuracy. For this reason,
Increasing the vibration damping properties of fiber reinforced composite materials has become an important issue.

In order to solve these problems, methods are being considered to increase the vibration damping of composite materials by increasing the vibration damping of matrix resins. This is a method of creating a composite material using a resin that has increased vibration damping properties by adding a ductility imparting agent such as polyethylene glycol, polypropylene glycol, or liquid rubber to a matrix resin.

However, although the vibration damping properties of the resin can be improved by several tens of times by adding a ductility agent, the vibration damping properties of the composite material can only be increased by several times, and this is accompanied by a large decrease in rigidity. Not the point. The present invention is intended to solve the above-mentioned problems, and its purpose is to provide a fiber-reinforced composite material with high vibration damping properties.

(Means for Solving the Problems) The present invention provides sheet or mat-like reinforcing materials made of inorganic reinforcing fibers such as carbon or glass fibers or organic reinforcing fibers such as aramid fibers, and epoxy resin or unsaturated A process of stacking the reinforcing material while impregnating it with a matrix resin such as polyester resin, or a process of laying and stacking the reinforcing material impregnated with the matrix resin in advance on a mold, and a process of stacking the reinforcing material impregnated with the matrix resin in part or all of the matrix resin. An object of the present invention is to provide a method for producing a fiber-reinforced composite material, which is characterized by comprising a step of providing an elastic material.

(Function) In the production method of the present invention, a resin-impregnated sheet or mat-like reinforcing fiber material and a viscoelastic material are stacked and cured in a mold, so inorganic reinforcing fibers such as carbon and glass fibers or organic reinforcing fibers such as aramid fibers are used. It is possible to realize a fiber-reinforced composite material in which a composite material layer consisting of a resin and a viscoelastic layer are integrated. The composite material has great vibration damping properties due to the vibration damping effect of the viscoelastic material between the layers.

Examples of resins to be impregnated into the reinforcing fibers include epoxy resins made by combining polyfunctional epoxy resins such as diglycidyl ether bisphenol A and polyglycidyl etherified novolacs with curing agents, addition-curing polyimides, condensed polyimides, unsaturated polyester resins, and Thermoplastic resins such as polyetheretherkedone are preferred. Further, as the viscoelastic material, known materials such as uncured materials, semi-cured materials (B-stage), cured materials, thermoplastic elastomer sheets such as polyolefin and polyether, and silicone rubber sheets can be used.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the flow of the method for producing the fiber-reinforced composite material of the present invention. A sheet or mat-shaped reinforcing material is laid out in a mold of the desired shape and laminated while being impregnated with Bematrix resin.

Once the laminate has reached a suitable thickness, the viscoelastic material is applied to some or all of the reinforcement. After that, the reinforcing material is laid down and laminated again while impregnated with Bematrix resin. After repeating the above steps until the required configuration is achieved,
After curing, demolding and shaping are performed.

In this embodiment, a reinforcing material not impregnated with a matrix resin was used, but it is also possible to use, for example, a prepreg sheet in which reinforcing fibers are impregnated with a matrix resin in advance.

FIG. 2 shows a cross section of a structure manufactured using the manufacturing method of the embodiment shown in FIG. In this example, randomly oriented carbon fiber mats were laid out in a bowl-shaped mold as shown in the figure. An epoxy resin (uncured) mixed with an amine curing agent was used as the matrix resin, and a polyolefin sheet was used as the viscoelastic material. As is clear from the figure, it has a structure in which a CFRP layer 1 made of carbon fiber and epoxy resin and a polyolefin sheet 2 are laminated and integrally formed.

FIG. 3 shows the relationship between the loss coefficient and frequency of the composite material of the example. Bending vibration was applied to the composite material test piece and measured. In the figure, the solid line shows the properties of the composite material of the example, and the broken line shows the properties of the fiber-reinforced composite material produced by the conventional production method. In both cases, the loss coefficient was determined 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 greater vibration damping characteristics than the conventional material.

(Effects of the Invention) As described above, according to the present invention, it is possible to realize a fiber-reinforced composite material with high vibration damping characteristics, which can prevent failures of on-board equipment in space structures such as artificial satellites, and reduce antenna position accuracy. It has the effect of solving the noise problem caused by automobiles, etc.

[Brief explanation of drawings]

Figure 1 is a flow diagram of a method for manufacturing an example of the present invention, Figure 2 is a cross-sectional view of a composite material manufactured using the manufacturing method of the example, and Figure 3 is a diagram showing the loss factor of the composite material. .

Claims (1)

[Claims] A process of laying sheets or mat-like reinforcing materials made of inorganic reinforcing fibers or organic reinforcing fibers on a mold and stacking them while impregnating them with a matrix resin, or laying the reinforcing materials pre-impregnated with a matrix resin on a mold and stacking them side by side. A method for producing a fiber-reinforced composite material, comprising the steps of: and a step of providing a viscoelastic material on a part or the entire surface of the reinforcing material impregnated with the matrix resin.