JPS58205728A - Preparation of forming by composite material - Google Patents

Abstract

PURPOSE:To prepare efficiently and reasonably a composite product having strong material characteristics by a method wherein a cylindrical structure of fibrous threads having electrical heating properties is impregnated and coated with thermoset resin, then heated electrically to harden resin. CONSTITUTION:To take an example, film having mold releasing effect is inserted into the hollow part of cylindrical structure where wefts 2 are wound crossing suitably with warps 1 that are made of fibrous threads (such as carbon fiber etc.) of which part or all have electrical heating properties and arranged in a cylindrical form. Then, the film is impregnated and coated with thermoset resin to form a resin layer 5, the external periphery of the resin layer 5 is coated with film tape 6 to hold the shape, etc. then the resin is heated electrically and hardened to obtain the intended composite forming.

Description

[Detailed description of the invention] The present invention relates to a novel method for manufacturing composite material moldings.

Carbon fibers or silicon carbide fibers, which are often used as reinforcing materials, have properties such as high strength, high elasticity, and low specific gravity, so they can be made into high-performance composite materials by impregnating and coating them with resin and curing them. In recent years, there has been a strong tendency to replace metal materials.

In order to effectively demonstrate the reinforcing effect of fiber threads, which are reinforcing materials for composite material molded products, the orientation and arrangement of the fiber threads within the molded product are very important factors, and the shape of the molded product Various orientations and arrangements must be made. Among various molded products, those having a hollow columnar shape are the most common among many molded products, and are used for various purposes.

The present invention uses a thermosetting resin in a hollow columnar structure in which weft yarns are wound around a group of warp yarns arranged in a hollow column shape, which are partially or entirely made of fiber threads that generate heat when energized. This is a method for producing a composite material molded product, which is characterized in that the structure is impregnated with and coated with the resin, and then the structure is heated with electricity to cure the resin.

When carrying out the present invention, a hollow columnar structure is obtained by winding the warp yarns, some or all of which are arranged in a hollow columnar manner, consisting of fiber threads that generate heat when energized, while intersecting the warp yarns as appropriate. Get a body.

Next, the hollow columnar object as a reinforcing structure constituted by the fiber threads has a very important characteristic that in addition to having tensile compressive strength with respect to the column axis, compressive crushing strength in the direction perpendicular to the column axis is very important. must be taken into account. In order to fully exhibit both of these characteristics in the molded article, reinforcing fibers may be arranged in the columnar axis direction and in the direction perpendicular to the axis, that is, in the circumferential direction of the columnar article. For example, the structure shown in FIG. 1 is a hollow columnar structure in which weft yarns 2 are wound around a group of warp yarns arranged in a hollow columnar manner while appropriately intersecting with warp yarns 1, and this structure consists of reinforcing fiber yarns. Since the stripes are arranged in the axial direction and circumferential direction of the column, it has a sufficient reinforcing effect as a hollow columnar object.

Next, this hollow columnar structure is impregnated and coated with a thermosetting resin. For this purpose, for example, as shown in FIG.
It is preferable that the resin layer 5 is formed by inserting the weft into the hollow part of the structure made of the weft and weft threads 2, and then impregnating and coating with a thermosetting resin. The outer periphery of this resin layer 5 is covered with a shrink film tape 6 having a release effect to maintain its shape.

A preferred embodiment for electrically heating the resin-impregnated and coated hollow columnar structure or composite thus obtained is shown in FIG. In FIG. 6, a composite mouth is obtained by impregnating and coating the central part of the hollow columnar structure A with a thermosetting resin. Both ends of the composite mouth are not impregnated with resin and are left as they are in the structure. Then, these ends are gripped by chucks 7 and 7' so as to serve as electrodes. When the chain 7, 7' is connected to the power source 8 and the variable resistor 90 circuit and energized, the composite opening is heated by generation of Joule heat, and the resin reaches a predetermined temperature and hardens accordingly.

In the energization heat treatment, since the structure made of the reinforcing fiber yarn of the present invention is continuous in both the warp and weft, it is possible to energize all the yarns.

Therefore, electricity is completely applied and heating can be performed uniformly. In this way, electrical heating, unlike ordinary atmospheric heating, is an extremely efficient heat treatment method because it is internal heating that heats only the necessary amount in the necessary areas, so there is no unnecessary release of heat.

Further, according to the method of the present invention, a molded product having very strong material properties can be processed efficiently and rationally.

It should be noted that it is not necessarily an absolute condition that both the warp and the weft of the yarn constituting the structure are electrically heat-generating, and the purpose can be sufficiently achieved with just the warp.

Example A hollow columnar structure with a diameter of 20 mm as shown in Fig. 1 was created using yarn consisting of 6,000 carbon fibers (one diameter of about 8 μm), and an insulating film was wrapped around this structure. Insert a cylindrical public holiday with a diameter of 195 mm. The structure is impregnated with a phenolic epoxy resin stabilized by adding a crosslinking agent and a catalyst and made liquid at 60° C. to a resin weight ratio of 45%. Next, the entire composite was covered with a polyester shrink film release-treated tape, and both ends of the structure to which no resin was attached were gripped with chucks, and a current of 10 V and 8 A was applied for 15 minutes. So 13
After heating to 0°C, the resin is kept at this temperature for 40 minutes to cure the resin.

The obtained hollow columnar composite material molded product has a crushing strength 6.7 times higher than that of a hollow columnar product of the same shape, same size, and resin-containing material in which carbon fibers are arranged only along the column axis. The bending fracture strength was also 4°2 times higher.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a hollow columnar structure used in the present invention;
Figure 2 is a cross-sectional view of a composite body shown in Figure 1 impregnated with resin and molded into a hollow column shape, and Figure 6 is heated by electricity through the structure shown at both ends of the composite body shown in Figure 2. 1 is a process diagram for explaining a processing method, and in the figure, symbol 1 indicates one warp thread, 2 indicates a weft thread, 3 indicates a columnar upper body, and 5 indicates a thermoplastic resin. Applicant Mitsubishi Rayon Co., Ltd. Agent Patent Attorney Masao Kobayashi 7- Blue 1 Figure

Claims (1)

[Claims] A hollow columnar structure is impregnated with a thermosetting resin and coated with a thermosetting resin.A hollow columnar structure in which weft yarns are wound around a group of warp yarns arranged in a hollow column shape, some or all of which are made of fiber threads that generate heat when energized, intersects with the warp yarns as appropriate. A method for producing a composite material molded article, which comprises curing the resin by heating the structure with electricity.