JPH0357627A - Fiber reinforced plastic molded form having three-dimensional curved surface - Google Patents

Abstract

PURPOSE:To manufacture a fiber reinforced plastic molded form which is excellently draped with a three-dimensional curved surface and free from generation of a wrinkly by forming long fiber for reinforcement into a reed screen-shaped sheet by connection yarn and making this connection yarn extensible and contractible or making the entangling structure of this connection yarn extensible and contractible. CONSTITUTION:In a reed screen-shaped sheet S, a plurality of pieces of bundlelike long fiber 1 for reinforcement are arranged in one direction while these alternately hold the gaps and are made adjacent. Connection yarn 2 connects these bundlelike long fibers for reinforcement while it is entangled therewith. Connection yarn 2 is formed of such extensible and contractible yarn that yarn itself has stretching properties. Further when long fiber for reinforcement is connected, the entangling structure is made extensible and contractible. Many pieces of long fiber for reinforcement can be relatively moved to the direction crossing the longitudinal direction of fiber and also relatively moved to the longitudinal direction of fiber via such connection yarn as this. Therefore when this reed screen-shaped sheet S is molded together with resin by a mold having a three-dimensional curved surface, long fiber 1 for reinforcement is changed so as to be draped in accordance with this three-dimensional curved surface while the position of long fiber is changed to the longitudinal direction of fiber or to the direction crossing it with each other. Therefore, this sheet S is not creased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fiber-reinforced resin shaped body having a cubic curved surface and using long fibers as reinforcing fibers.

[Prior art]

Conventionally, when shaping a fiber-reinforced resin molded body having a three-dimensional curved surface such as a helmet, short fibers (chopped fibers) have been used as reinforcing fibers. Although long fibers have a mechanically higher strength utilization rate than short fibers, the reason why short fibers are used in this way is as follows.
This is because long fibers create wrinkles when they are made into a sheet-like fabric and are made to conform to a three-dimensional curved surface, making it difficult to conform to the curved surface. In sheet-like fabrics made of long fibers, the wrinkles not only deteriorate the appearance of the shaped body but also cause variations in strength.

[Problem to be solved by the invention]

An object of the present invention is to provide a fiber-reinforced resin or shaped body that uses mechanically advantageous long fibers as reinforcing fibers and has a cubic curved surface that conforms well to the cubic surface and does not generate wrinkles. .

[Means to solve the problem]

The present invention achieves the above object by forming a blind-like sheet in which a large number of reinforcing long fibers aligned in one direction are intertwined with connecting threads in a direction that crosses the reinforcing long fibers, and the connecting threads are or the intertwined structure of the connecting threads is made stretchable, and the plurality of reinforcing long fibers are movable relative to each other in the longitudinal direction of the fibers and in the direction crossing the longitudinal direction of the fibers. The screen is characterized in that the screen-like sheet is shaped into a curved surface together with the resin along a cubic curved surface.

In the present invention, both conventionally known inorganic fibers and organic fibers can be used as the long fibers used for resin reinforcement. The long fibers are preferably carbon fibers or glass fibers. High-strength, high-modulus fibers such as aramid fibers are used, but polyamide fibers with specially increased strength and modulus are also used. Polyester fiber. Polyvinyl chloride fibers, polyethylene fibers, etc. can also be used.

As the resin used in the present invention, thermosetting resins are preferred, but thermoplastic resins can also be used. Examples of the thermosetting resin include epoxy, unsaturated polyester, and vinyl ester. Examples include resins such as polyimide and phenol. Examples of thermoplastic resins include polyamide, polyester, polyethylene, polypropylene, and polyacetal. Examples include resins such as polycarbonate.

The connecting yarn used in the present invention is not for reinforcing the resin, but for connecting the reinforcing long fibers to the blind-like sheet, so it does not necessarily have high strength or high elastic modulus like the reinforcing long fibers. It doesn't have to be. Examples of the yarn include fibers such as polyamide, polyester, acrylic, polyvinyl chloride, polypropylene, polyethylene, and rayon.

This connecting yarn is used either as a stretchable yarn (stretch yarn) in which the yarn itself is stretchable, or in such a manner that the intertwined structure when the reinforcing long fibers are connected has stretchability.

By interposing such a connecting yarn, a large number of reinforcing long fibers can be moved relatively in a direction intersecting the longitudinal direction of the fibers, and also in the longitudinal direction of the fibers. The stretchable yarn in which the connecting yarn itself exhibits elasticity may be either a torque yarn or a non-torque yarn.

Examples of the torque yarn include processed yarns made by a twist-heat set-untwist method, a false twist method, or a hard twist method. In addition, non-torque yarns can be used using the rubbing method or the molding method. Processed yarns made by either method can be mentioned. Further, the elastic yarn may be made of a resin such as polyurethane, which itself has elasticity.

A knitted structure can be mentioned as a structure that makes the intertwined structure of connecting yarns stretchable.

Figure 1 shows an example of a blind-like sheet made of long fibers used for reinforcing the fiber-reinforced resin shaped body of the present invention.
This blind-like sheet S has a plurality of bundles of reinforcing long fibers 1 arranged in one direction while adjoining each other with gaps, and each of these bundles of reinforcing long fibers being intertwined with connecting threads 2. I'm trying to connect them. Further, the connecting threads 2 are provided intermittently at relatively long intervals in the longitudinal direction of the reinforcing long fibers 1.

In such a blind-like sheet S, the connecting threads 2 themselves are stretchable threads, or the interlacing structure with respect to the reinforcing long fibers has stretchability.

Therefore, due to the elasticity of the connecting yarn 2, the adjacent reinforcing long fibers 1 can move relative to each other in the direction that the connecting yarn 2 crosses, that is, the direction that intersects the longitudinal direction of the fibers.
Depending on the external force applied to the screen-like sheet S, the sheets may be separated from each other,
You can get close. In addition, the reinforcing long fibers 1 are not firmly held by the connecting yarns 2 due to the elasticity of the connecting yarns 2, and are able to slide in the longitudinal direction of the fibers. Therefore, the adjacent reinforcing long fibers 1 can also move relative to each other in the fiber longitudinal direction.

Therefore, when this blind-like sheet S is formed with a resin in a mold having a cubic curved surface, the reinforcing long fibers 1 change their positions in the longitudinal direction of the fibers and in the direction crossing this, corresponding to the cubic curved surface. It changes to fit in. Therefore, wrinkles do not occur in the screen-like sheet S.

In the screen-like sheet S, since the reinforcing long fibers 1 are arranged in one direction, the reinforcing direction of the fiber-reinforced resin is made unidirectional. Therefore, when this screen-like sheet S is used for a fiber-reinforced resin or shaped body, it is desirable to combine a plurality of sheets so that the reinforcing direction is anisotropic. For example, the second
As shown in the figure, by laminating two blind-like sheets S such that the reinforcing long fibers 1 of both sheets are orthogonal to each other at 90 degrees, the reinforcing directions can be given in directions orthogonal to each other. In addition, as shown in Figure 3, if four sheets of blind-shaped sea +-S are stacked with the reinforcing long fibers 1 shifted by 45 degrees from each other, the anisotropy will be further enhanced, and it will become almost isotropic. You can get close.

FIGS. 4 and 5 each illustrate a fiber-reinforced resin molded body formed into a helmet. Both helmets 3 are reinforced by the screen-like sheet S. The helmet 3 in Fig. 4 uses the blind-shaped sheet S only in the upper part, and the other parts are made of resin only, or
It is reinforced with the same short fibers as before.

On the other hand, the helmet 3 shown in FIG. 5 uses the screen-like sheet S throughout.

In these helmets 3, each of the screen-like sheets S corresponds well to the three-dimensional curved surface without wrinkles, so that the appearance of the helmet does not deteriorate and the strength does not vary.

In addition, the blind-like sheet S has a higher mechanical reinforcement efficiency than one reinforced with short fibers, so it requires less fiber to achieve the same strength, and the entire helmet (fiber-reinforced resin molded body) It can be made lighter.

〔Effect of the invention〕

As described above, the fiber-reinforced resin molded article of the present invention has the following features: 4. The connecting thread that connects a large number of reinforcing long fibers aligned in one direction to the screen-like sheet is made elastic. Alternatively, the intertwined structure of the connecting threads is made stretchable, and the plurality of reinforcing long fibers are formed into a blind-like sheet that is movable relative to each other in the longitudinal direction of the fibers and in the direction crossing the longitudinal direction of the fibers. The long fibers conform well to three-dimensional curved surfaces and do not cause wrinkles.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a blind-shaped sheet used in the fiber-reinforced resin shaped body of the present invention, and FIGS. 2 and 3 are explanatory diagrams illustrating the case where a plurality of blind-shaped sheets are used in combination, respectively. , FIG. 4, and FIG. 5 are longitudinal cross-sectional views of helmets molded using the same blind-like sheet. 1... Reinforcing long fiber, 2... Connecting thread, S... Blind-like sheet.

Claims (1)

[Claims] A blind-like sheet is formed by intertwining a large number of reinforcing long fibers aligned in one direction with connecting yarns in a direction that crosses the reinforcing long fibers, and the connecting yarns are made elastic or the connecting yarns are The intertwined structure of the threads is made stretchable, and the plurality of reinforcing long fibers are made into a blind-shaped sheet that is movable relative to each other in the longitudinal direction of the fibers and in the direction crossing the longitudinal direction of the fibers, and the blind-shaped sheet has a three-dimensional curved surface. A fiber-reinforced resin molded article having a tertiary curved surface formed along the curved surface along with resin.