JPS58215314A - Molding method of composite material molded article - Google Patents

Abstract

PURPOSE:To reduce the working cost of a molding considerably, by feeding an electromagnetic energy to the laminate composed of a reinforcing fiber and the matrix resin which contains the conductive carbon material of 1.0-70wt% to the matrix resin and molding it. CONSTITUTION:A carbon material containing matrix resin is prepared by adding the conductive carbon material of 1.0-70wt% to the matrix resin and mixing them well. Then, a reinforcing fiber is made mat like after being impregnated with the carbon containing matrix resin and a laminate is obtained by laminating this or laminating alternately the reinforcing fiber and the carbon containing matrix resin which is molded film like. By feeding an electromagnetic energy to the obtained laminate and treating it a composite material molded product is obtained. The working cost of a molding can be reduced considerably in this way.

Description

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

Composite material moldings have traditionally been used in aircraft, vehicles, X-ray-related equipment, audio-related equipment, as well as sports and leisure products such as fishing rods, golf shafts, tennis rackets, etc. It is expected that

In addition to glass fiber, aromatic polyamide fibers, boron fibers, and carbon fibers have been developed as reinforcing fibers used in this composite material, and extensive research has been conducted to give this composite material the ultimate performance. ing.

However, no technological progress has been made in molding methods, particularly resin curing and melt shaping, and hot press molding and autoclave molding are the typical molding methods used in lamination years. 9 However, although the hot press molding method is used for products with relatively simple shapes and relatively thin walls, such as plate-shaped molded products, there are problems with the parallelism and flatness of the top and bottom surfaces of the hot press, and Because thermal conductivity differs significantly between the center and edges of the surface, it can only be applied to small objects. For this reason, autoclave forming methods are used to mold large-sized composite materials. This forming method includes a method using a heated inert gas and a method using steam heating, but these methods have the disadvantage that the molding process is extremely long and the productivity and thermal efficiency are poor, resulting in a significantly high molding cost.

The present invention has improved these drawbacks, and has a 1.0 to 70
A method for forming a composite material molding, characterized by supplying electromagnetic energy to a laminate made of a matrix resin containing % by weight of a conductive carbon material. It can be either fiber or organic fiber, but it can be made of glass fiber, aromatic nylon fiber,
Boron fibers and alumina fibers are preferred. Either long fibers or short fibers may be used, or two or more types of fibers may be used in combination.

Maru-IJ lux resins include thermosetting resins such as phenolic resins, polyester resins, epoxy resins, thermoplastic resins such as nylon 6, nylon 66, P
ET%PBT, polycarbonate, polyolefin,
Polyacetal, ABS, etc. are used.

Further, as the conductive carbon material, for example, acetylene black, graphite, fibrous carbon, etc. can be used. Fibrous carbon is particularly preferred. These carbon materials have a volume resistivity of 10
1 to 10 −5 Ω·m, particularly 10 −2 to 10 −4 Ω·m is preferable. When the volume resistivity exceeds 101 Ω·σ, the efficiency of electromagnetic energy utilization decreases significantly, and on the other hand, it is difficult to produce a carbon material with a volume resistivity of less than 10 −5 Ω·σ.

In carrying out the present invention, a carbon material-containing matrix resin is prepared by adding 1.0 to 70% by weight of a conductive carbon material to the matrix resin and mixing well.

The amount of conductive carbon material is 1.0% by weight of the matrix resin.
If it is less than that, insufficient heat cannot be supplied,
Moreover, if it exceeds 70% by weight, it will not play its role as a matrix resin, and a high-strength composite material will not be obtained.

Next, a laminate consisting of reinforcing fibers and a carbon material-containing matrix resin is manufactured. The laminate can be manufactured by impregnating reinforcing fibers with a carbon-containing matrix resin, forming them into a mat, and then laminating them, or by alternately laminating reinforcing fibers and carbon-containing matrix resin formed into a film. A method is used.

When the laminate thus obtained is treated by supplying electromagnetic energy, a composite material molded article is obtained. Methods for supplying electromagnetic energy include a method of supplying direct current or alternating current to the laminate, a method of inserting the laminate into a coil and then supplying high frequency to the coil, and a method of irradiating the laminate with microwaves. used. Industrially, it is preferable to use the microwave irradiation method. Microwave means electromagnetic waves with a frequency of 1 + - 1 Hz to I GHz.

When irradiating with microwaves, it is necessary that the laminate be in the same shape as the mold.For this reason, the laminate on the mold is coated with a film-like substance, and the seal between the films is sufficiently secured. It is preferable to perform vacuum degassing.It is also preferable to pressurize with nitrogen gas or air at about 1 to 20 kg/cm2 as necessary.

The mold is preferably made of a material that absorbs little electromagnetic energy and is heat resistant, such as glass, ceramics, Teflon, and the like.

As a film-like material, a material with excellent heat resistance and a small dipole moment is preferable, such as polyester film, fluorine-polymer #Ushishi=] (polyvinylidene fluoride, polytetrafluoroethylene, +imide film, etc.). .

The temperature increase program of the laminate can be adjusted by the amount of electromagnetic energy supplied (output) and the irradiation time.According to the method of the present invention, by supplying electromagnetic energy, the carbon material in the matrix resin becomes a heating source. Since the surrounding resin is cured or melted, it is possible to uniformly raise the temperature of the inner and outer surfaces of even large and complex-shaped laminates. Therefore, the performance of the molded product is significantly improved compared to the autoclave molding method. Furthermore, since electromagnetic energy is used, the temperature of the laminate can be easily controlled, resulting in excellent reproducibility and is extremely advantageous industrially. Furthermore, since only the laminate is heated, energy consumption is significantly reduced.

Furthermore, the time required to heat up the laminate can be shortened, and the molded product can be taken out immediately without having to wait for the temperature of the heating device to drop as in the autoclave molding method, so the molding cycle can be shortened by one inch.

Example 1 100 parts by weight of an epoxy resin precursor and 15 parts by weight of carbon fibers having a length of 5fi were added and mixed, and this mixture was impregnated into a plain weave cloth made of glass fibers, and the mixture was semi-cured to produce a glass cloth prepreg. An aromatic polyamide cloth grip preg is produced by impregnating an 8-ply sateen cloth with aromatic polyamide fibers. Glass cloth prepreg is laminated on the inner layer of a glass flat mold to a thickness of 20 mm, and aromatic polyamide cloth prepreg is laminated on both sides of the glass cloth prepreg to a thickness of 5 mm. The size of this laminate is 1o.

It is OX800m.

After this laminate is covered with a polyethylene film and sufficiently sealed, the inside of the system is evacuated using a vacuum pump, and the laminate is inserted into a container equipped with a microwave generator. Next, the temperature was raised from room temperature to 160°C in 15 minutes, and further heated for 160°C.
After holding at 0°C for 45 minutes, the laminate is immediately taken out and air cooled.

As the microwave generator, we used a device that can switch outputs in two stages: i kW and 2 kW, and the microwave frequency was 2 kW.
．． 45 GHz. The temperature of the laminate was controlled by switching the output or turning the power on and off.

It took 65 minutes from putting the laminate into the container to taking it out, which is one fraction of the time required by the conventional autoclave method.
/3 to 1/4. The obtained molded product had no defects and had a good shape.

Example 2 100 parts by weight of nylon 66 and 6 strips of carbon fiber 25
Add parts by weight, knead with an extruder, and extrude into a film from a T-die. This film and glass cloth were covered with a laminated film on a Teflon flat mold to a thickness of 40 mm after molding, and after sufficient sealing, the system was evacuated. This laminate was loaded into a pressurized container equipped with a microwave generator with an output of 20 kW, and the output was 15 ky/cm.
After pressurizing to 2G, microwave irradiation is performed for 15 minutes. Immediately after irradiation, the laminate is transported outside the system and cooled in air. The obtained molded product had no defects and had a good shape. Moreover, the time required from loading the laminate to taking it out was 20 minutes.
The molding time was significantly reduced.

Applicant: Mitsubishi Rayon Co., Ltd. Agent: Patent attorney Masao Kobayashi

Claims (1)

[Claims] 1. 1°0 for reinforcing fibers and matrix resin
A method for forming a composite material molding, characterized in that electromagnetic energy is supplied to a laminate made of a matrix resin containing ~70% by weight of a conductive carbon material. 2. The method according to claim 1, characterized in that short carbon fibers are used as the conductive carbon material. 6. When supplying electromagnetic energy to the laminate,
A method according to claim 1, characterized in that after the laminate is coated with a film-like material, the pressure inside the film system is reduced. 4. The method according to claim 1, characterized in that microwaves are used as the electromagnetic energy.