JPH0751322B2 - Whisker reinforced plastic manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a reinforced plastic composite material, and more particularly to a method for producing a whisker-reinforced thermoplastic resin composite material.

[Prior art] Reinforced plastic composite material produced by dispersing and integrating a reinforcing material dispersed phase in a base material matrix continuous phase as a whisker reinforcing material based on a thermoplastic resin is expected as an excellent industrial material having high strength Has been done.

Generally, for ease of handling, they are usually manufactured as preform intermediate products such as tablets, pills, pellets, biscuits, and then processed into final products. It is also possible to produce the final product in one step from the substrate and the reinforcement without going through the preform intermediate product, in which case injection molding techniques are usually used. In any case, when producing a fiber-reinforced plastic composite material, whiskers are dispersed in a resin in a plasticized and molten state and then cooled and solidified to produce a composite material, but a mixture of molten resin and whiskers is The mixing ratio of whiskers is the volume ratio (Volume
Fraction Vf) reaches a few 10% and loses fluidity, making it impossible to mix homogeneously. It is difficult to produce composite materials with high volume ratio of whiskers and excellent properties by these conventional methods. Met. The improvement of the volume ratio of the whiskers becomes particularly difficult when the powder base material and the whiskers are melt-mixed in one step and the injection molding is used to manufacture the final product, and the volume ratio is usually 12 to 13%. By forming a whisker preform and impregnating it with a resin, it is possible to obtain a product with a relatively high volume ratio compared to injection molding, but it is difficult to manufacture a uniform preform and the resin is added to the preform. There is a problem that it is difficult to obtain a suitable composite material because compression or cracking of the preform occurs during impregnation. Therefore, it is desired to realize a manufacturing method capable of solving the problems of these conventional techniques and manufacturing a whisker-reinforced composite material having excellent properties.

[Problems to be Solved by the Invention]

It is an object of the present invention to provide a method for producing a whisker-reinforced plastic which has a stable quality and is capable of freely controlling the volume ratio of whiskers in a product and has a good dispersion of whiskers.

[Means for Solving the Problems]

According to the present invention, in manufacturing a whisker reinforced plastic, one end is connected to a vacuum means, and a slider is slidable with an end connected to the vacuum means of a substantially cylindrical container. Fill the powder filling chamber defined between the child and the powder mixture of whiskers and thermoplastic resin, and make the powder filling chamber substantially vacuum by the vacuum means, heat the container and slide the slider. A method for manufacturing a whisker reinforced plastic is provided, which comprises applying pressure to the powder filling chamber through the whiskers.

The whiskers in the present invention include single crystal fibers and vapor phase growth fibers in general, and specifically include silicon carbide whiskers, silicon nitride whiskers, potassium titanate whiskers, vapor growth carbon fiber graphite whiskers and the like.

[Action]

By using a powder or solid mixture of whiskers and thermoplastic resin as the material to be used, it is possible to arbitrarily adjust the mixing ratio of these and to make the volume ratio of whiskers in the product higher than in the past. .

When the powder filling chamber filled with the powder mixture of whiskers and thermoplastic resin is heated to a substantially vacuum by heating with a vacuum means and pressure is applied, even the gas remaining between the whiskers and the resin is effective. After being removed, the molten resin sufficiently penetrates into the inside of the fine structure, the structure becomes extremely dense, and the impregnation of the resin reaches a saturation value, so that the quality is stabilized and defects such as voids in the product are removed.

〔The invention's effect〕

The whisker reinforced plastic produced by the method for producing a whisker reinforced plastic of the present invention has a good dispersion, and the volume ratio of the whiskers in the product can be arbitrarily set, and it is possible to make it much higher than in the past, and its variation Slightly stable in quality. Further, since the resin is sufficiently impregnated, it is possible to obtain a whisker reinforced plastic having a dense structure and higher strength than the conventional one.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the following examples.

Example 1 Diameter of about 0.2 μm and length of about 20 μm produced by vapor deposition
m of vapor-grown carbon fiber heat-treated with 25 g of graphite whiskers and thermoplastic resin nylon 6.6 with an average particle size of 3 μm,
30 g is uniformly mixed and filled in the powder filling chamber 10 of the apparatus shown in FIG. The whiskers used have a specific gravity of 2.25 and the thermoplastic resin has a specific gravity of 1.11. From these, the theoretical value of the volume ratio of whiskers in the product is calculated to be 29%.

A valve 12 provided in a pipe connecting the powder filling chamber 10 and a vacuum device (not shown) is opened to deaerate the powder filling chamber 10 to make a vacuum inside. If a suitable filter is provided between the powder filling chamber 10 and the valve 12, it is possible to prevent the powder from scattering to the vacuum device. For example, heating the powder filling chamber using a heating means such as a baking heater 14 and simultaneously heating the powder filling chamber.
Pressurize through 16. It is sufficient that the heating temperature is a temperature at which the thermoplastic resin is in a molten state in the powder filling chamber 10, for example, 220 to 240 ° C. The pressurizing pressure is preferably 10 kg / cm ² or more, and the volume of the powder filled in the powder filling chamber 10 gradually decreases as the process progresses, reaching about 20% of the initial volume and reaching a substantially constant value. . It takes about 30 minutes from the start of the volume reduction of the powder by heating and pressurization until it reaches a certain value and the process is completed. After operating the vacuum device and the valve 12 to return the powder filling chamber 10 to the normal pressure, the product is taken out. The properties of the whisker reinforced plastics obtained by this method are shown in Table 1.

Embodiment 2 Embodiment 1 except that the pressurizing means is a slider 20 (made of metal, plastic or rubber) driven by a liquid pressure medium 18 such as oil as shown in FIG. 1 (b). Table 1 shows the properties of the whisker-reinforced plastics obtained by this method, which produces whisker-reinforced plastics in substantially the same manner as.

Comparative Example 1 A graphite whisker preform was prepared in a cylindrical container, vacuumed, impregnated and solidified with molten nylon, a test piece was cut out, and the characteristics were examined. The results are shown in Table 1.

[Brief description of drawings]

FIG. 1 is an explanatory view conceptually showing the cross section of an apparatus used for carrying out the method for producing a whisker reinforced plastic of the present invention. FIG. 1 (a) uses a piston as a slider, and FIG. 1 (b) applies pressure by a liquid pressure medium. 10 …… Powder filling chamber 12 …… Valve 14 …… Baking heater 16 …… Piston 18 …… Liquid pressure medium 20 …… Slider

Claims (1)

[Claims] 1. When manufacturing a whisker reinforced plastic, an end and a slider connected to a vacuum means of a substantially cylindrical container in which one end is connected to a vacuum means and a slider slides inside. And a powder mixture of a whisker and a thermoplastic resin are filled in a powder filling chamber defined between and, the powder filling chamber is substantially evacuated by a vacuum means, the container is heated, and a slider is used. A method for producing a whisker reinforced plastic, which comprises applying pressure to a powder filling chamber by means of a pressure.