JPH02241710A - Forming mold of fiber reinforced resin formed item - Google Patents

Abstract

PURPOSE:To obtain the shape stability of a forming mold by a structure wherein a fiber reinforced resin layer is integrally provided on the forming surface side of a wooden matrix and a facial heating element is further provided on the fiber reinforced resin layer and a forming surface made of resin layer is furthermore provided so as to cover over the facial heating element. CONSTITUTION:The forming mold concerned is produced by integrally providing a fiber reinforced resin layer 2 on the forming surface S side of a wooden matrix 1 and further providing a facial heating element 5 on the fiber reinforced resin layer 2 and furthermore providing a forming surface S made of resin layer 7 so as to cover over the facial heating element 5. As the resin used for the fiber reinforced resin layer 2 laminated to the wooden matrix 1, epoxy resin, unsaturated polyester resin, polyvinyl ester resin, polyimide resin or the like is used. As the facial heating element 5 used, facial body, which generates heat by electrical charging, such as woven or braided material, which is produced by weaving or braiding thread-like heating element formed out of resin kneaded and mixed with carbon black, woven or braided material or non-woven fabric made of carbon fiber, film, which is formed out of resin kneaded with carbon black, facially arranged structure of Nichrome wire or the like is used. Due to the above-mentioned structure, the deformation of the wooden matrix is prevented from occurring and, at the same time, uniform heat distribution is given to the whole formed item, resulting in allowing to obtain a homogeneous formed item.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a mold used for molding fiber-reinforced resin molded articles.

[Prior art] Fiber-reinforced resin molded products such as windsurfing boards made by multi-IJ knocking thermosetting resin are produced by laminating a fiber base material and resin in a molding mold, or by pre-layering a fiber base material and a resin. It is made by laminating prepreg material impregnated with resin and then hardening and molding it. In such hardening molding, when the molding die is a metal mold, the mold is mounted on a hot press machine and heated and pressurized. However, as is well known, molds are very expensive, so high costs are unavoidable. Particularly in the case of large molded products, not only the cost of the mold but also the cost of the hot press machine increases, which is extremely disadvantageous from a human standpoint.

This high cost of molds can be avoided by using wooden molds. However, since wooden molds can be deformed by heating, it is difficult to harden and mold by direct heating, so molding at room temperature is forced.As a result, it takes a long time to harden and mold, and the hardening is insufficient. Therefore, after-curing is required, which has the disadvantage of poor productivity.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the problems of the conventional wooden molds mentioned above,
An object of the present invention is to provide a mold for a fiber-reinforced resin molded product, which has a heating element for direct heating built into the wooden mold, has shape stability that can withstand heating, and provides high productivity.

[F stage for solving problems]

The molding mold of the present invention that achieves the above object has a fiber-reinforced #44 fat layer integrally provided on at least the molding surface side of the wooden matrix,
The present invention is characterized in that one of the fiber-reinforced resin layers is provided with a sheet heating element and a molded surface of a resin layer covering the upper side of the sheet heating element.

In this way, the fiber-reinforced resin layer is provided on the wood matrix, giving it strength and rigidity, and the wood matrix does not easily deform even when heated directly.
Since the heating element is a planar heating element, uniform heat distribution can be given to the entire molded product, and a homogeneous molded product can be obtained.

The plywood used in the present invention is not particularly limited as long as it is made of wood, but it is made of plywood board 8
Plywood or the like is a preferred material.

In the present invention, the fiber reinforced resin layer laminated on the wood matrix is
It may be provided at least on the molding surface side of the mother mold, but if it is further provided on the surface opposite to the molding surface,
The durability against deformation and the like against heating can be made perfect. The resin used for this fiber reinforced phase i1M layer is not particularly limited, but epoxy resins, unsaturated polyester resins, polyvinyl ester resins, polyimide resins, etc. are preferably used. In particular, thermosetting resins such as epoxy resins and diunsaturated polyester resins are preferred resins. Further, as the reinforcing fibers for reinforcing the resin, any conventionally or commonly used reinforcing fibers can be used, and carbon fibers, glass fibers, aramid fibers, carbonized carbide fibers, etc. are particularly preferred.

In the present invention, the resin used for the resin layer constituting the molding surface is integrated into the above-mentioned wooden matrix! ! The same epoxy resin as the resin for the fiber-reinforced resin layer.

Unsaturated polyester resins, polybeer ester resins, one polyimide resin, etc. can be used, and thermosetting resins such as epoxy resins and two unsaturated polyester resins are particularly preferred. Although this resin layer may be made of resin alone, it is preferably a fiber-reinforced resin layer reinforced with reinforcing fibers.

The reinforcing fibers are the same carbon fibers as the fibers of the fiber-reinforced resin layer integrated into the wood matrix.

Glass 1at, aramid fiber, carbonized carbide fiber, etc. are preferably used.

The sheet heating element used in the present invention is a sheet heating element that generates heat when energized and has appropriate flexibility. For example, knitted fabrics woven or knitted with filamentous heating elements molded from resin mixed with carbon black;
Any of knitted fabrics or non-woven fabrics made from carbon fibers, films molded from resin kneaded with carbon black, and structures in which nichrome wires are arranged in a planar manner can be used. Particularly, among the above, a sheet heating element of a knitted fabric made of a filamentous heating element is most suitable because it can be uniformly aligned with a complicated molding surface and can be easily impregnated with resin.

This planar heating element is inserted between the fiber-reinforced resin layer fixed to the wooden matrix and the resin layer on the molding surface. When inserting this sheet heating element 1. ” - When the reinforcing fibers of the fiber-reinforced resin layer are conductive fibers such as carbon fibers, or when the resin layer is a fiber-reinforced resin layer and the reinforcing fibers are conductive fibers, Each must be inserted with an insulating layer interposed therebetween. This insulating layer has
Knitted fabrics such as glass fiber and aramid fiber are preferably used.

〔Example〕

FIG. 1 shows a longitudinal section of a mold for forming a fiber-reinforced resin molded article according to an embodiment of the present invention.

In this mold M, S is a molding surface, and 1 is a wooden matrix processed from a plywood board, and a fiber-reinforced resin layer 2 reinforced with carbon fiber is integrally pasted on the molding surface S side. There is. Furthermore, in this embodiment, a fiber-reinforced resin layer 3 reinforced with carbon fibers is also pasted on the lower surface of the wooden matrix 1. On the fiber-reinforced resin layer 2 pasted on the molding surface S side, a planar heating element 5, which is a filamentous heating element, is laminated via an insulating layer 4 made of glass fiber, and an insulating layer 6 made of glass fiber is further layered thereon. Intermediate. , the resin layer 7 of the molding surface S is laminated. In this embodiment, the resin layer 7 is a fiber-reinforced resin layer reinforced with carbon fibers.

The mold M configured in this manner can be heated by energizing the built-in planar heating element 5.

Using this mold M, for example, carbon fiber reinforced resin/
To mold a fiber-reinforced resin molded product in which the acrylic foam/I fiber-reinforced resin is constructed, the process is carried out as shown in Figure 2. First, epoxy resin is applied to the molding surface S of the mold M. A plurality of impregnated carbon fiber prepregs are laminated with an acrylic foam sandwiched between them, and a wooden mold 21 is placed on top of the laminate 20. This is wrapped in a vacuum bag 22 made of polyester film and connected to a vacuum source 6 via a hose 23. In this state, when the sheet heating element 5 of the mold M is heated and the inside of the vacuum bag 22 is evacuated, the second mold 21 presses the laminate 20 due to the atmospheric pressure, and in that state, it is hardened and molded. will be held.

Since this forming operation is performed by heating, the laminate 20
Cures quickly and can shorten molding cycles.

In addition, the mold M is a wooden matrix 1, but since the upper and lower surfaces are reinforced with fiber-reinforced resin layers 2.3, it exhibits good dimensional stability even when directly heated, and will not be deformed by heating. do not have. Furthermore, since it is made of a wooden matrix 1, it is lightweight and extremely easy to handle. Furthermore, since the heating element built into the mold M is the planar heating element 5, the temperature distribution is uniform over the entire surface of the laminate 20, and a homogeneous molded product can be obtained.

The method of using the mold M of the present invention is not limited to the usage example shown in FIG.
Alternatively, the vacuum bag 22 made of a resin film may be directly corrugated and heat-formed. Alternatively, as shown in FIG. 4, the mold M of the present invention is used not only for the lower mold 4° but also for the upper mold 21, and these image molding molds M and M are sandwiched between cold presses 41 and 42. So that it is heated and molded.

But that's fine.

[Effects of the Invention] As described above, the mold of the present invention has the fiber-reinforced resin layer integrally provided at least on the molding surface side of the wooden matrix.
Although it has a built-in heating element for direct heating, it has the shape stability to withstand heating.

In addition, since the resin is cured and molded by direct heating, the molding cycle can be shortened and high productivity can be achieved. Furthermore, since the heating means is a planar heating element, a uniform temperature distribution can be obtained, and a homogeneous molded product can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a molding die according to an embodiment of the present invention;
Figure 2 is an explanatory diagram of the molding operation using the same mold, Figure 3
FIG. 4 and FIG. 4 are explanatory diagrams showing still other usage examples of the same molding die. DESCRIPTION OF SYMBOLS 1... Wooden matrix, 2.3... Fiber-reinforced resin layer, 4゜6... Insulating layer, 5... Planar heating element, 7... Resin layer, M... For molding Mold, S...molding surface.

Claims (1)

[Claims] A fiber-reinforced resin, in which a fiber-reinforced resin layer is integrally provided on at least the molding surface side of a wooden matrix, and a molding surface of a sheet heating element and a resin layer covering the upper part of the sheet heating element is provided on the fiber-reinforced resin layer. A mold for molding molded products.