JPS60155438A - Manufacture of fiber-reinforced plastic container - Google Patents

Abstract

PURPOSE:To obtain a high-strength FRP container by a method wherein a fiber material layer is covered with an outer die having a lower open end and an upper deairing port to form a circular space and after a vacuum deairing is done from the upper deairing port, a liquid resin is injected from the circular space. CONSTITUTION:Following an evacuation, a low-viscosity and long-time usable epoxy resin is injected from an injection port 8. The resin injected initially flows circumferentially in a space 7 and is retained down temporarily in the space 7. As the amount of the injected resin increases, the liquid surface thereof rise and then, reaches the rim of a glass cloth 2 all at once in the entire circumference thereof. Thereafter, the cloth is impregnated with the resin along the height by a capillary action while the remaining air is forced to discharge at the deairing port 5 corresponding to the capacity equivalent to that occupied by the resin. Thus, the impregnation is completed with the overflow of the resin at the deairing port 5 and subsequently, the resin is hardened by the ordinary resin hardening method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fiber reinforced plastic container! This invention relates to a manufacturing method.

[Technical background of the invention and its problems]

Superconducting boloidal coils are necessary to realize a nuclear fusion reactor. At the same time, the cryogenic container housing the coil must be protected against eddy current loss. Voloidal coils require pulsed current changes, so if the coil containment vessel is superconducting, the build-up of thin current is unavoidable, resulting in C loss.The coil becomes superconducting and energy loss is zero. Even so, the efficiency is poor as long as there is this container loss.

For this reason, an insulating container may be considered, but it must meet the following strict specifications.

■ Cracks must not live under the cryogenic temperatures filled with liquid helium.

■ The superconducting coil quenches and the liquid helicum does not rupture due to the high pressure that evaporates.

■ Gas helium is transparent.

■ It has excellent insulation properties.

In order to meet specification (1) of these requirements, it is necessary to use fiber reinforced plastic (FRP). However, since the container shape is generally cylindrical, it cannot be covered by commercially available laminate manufacturing technology.

In order to meet the specifications (2), the matrix resin must be uniformly dispersed, and if there is a pool of resin or a knee, thermal stress will concentrate and cracks will occur.

According to the specifications of ■, there should be no cracks or voids inside.

Glass fiber-reinforced epoxy resin compositions are considered as a possibility to meet these demands. Moreover, since voids must not be included, it is necessary to adopt a manufacturing method that employs a so-called vacuum impregnation method in which the gas fiber layer to be impregnated is vacuum degassed and replaced with resin.

However, even in the vacuum impregnation method, resin impregnation is difficult depending on the direction in which the reinforcing fibers are laminated, and voids are often left behind.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a highly reliable, high-strength FRP container that does not include a protrusion, therefore does not crack even when used as a liquid helium-filled container, and is resistant to helium gas permeation. .

[Summary of the invention]

In order to achieve the above object, in the manufacturing method of the present invention, a fibrous material layer is formed on the outer periphery of an inner mold having a lower open end, and the outside of this fibrous material layer is defined as a lower open end and an upper degassing port. and is sandwiched between the lower open ends of the inner mold and the outer mold to form an annular space in which the fibrous material layer does not exist, and vacuum degasses from the upper deaeration port to form the annular space. The liquid resin is injected into the fibrous material layer, and the injected resin is guided in the circumferential direction to make conditions for resin infiltration into the fibrous layer uniform in the circumferential direction.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Figure 4 is a cross-sectional view showing the middle of a manufacturing method according to an embodiment of the present invention. A glass cloth 2 is wound around the inner impregnating tank 1. Since the inner impregnating tank 1 also serves as a mandrel for glass cloth, it must be mechanically strong, but it may be separable as long as the cylindrical part and the hemispherical top part are integrated. The glass cloth 2 is wound around the open end 3 of the inner impregnating tank 1 leaving the edges intact. The outer surface C of the glass cloth 2 is covered with an outer impregnating tank 4 that is in close contact with the outer surface of the wound glass cloth 2. A deaeration port 5 is provided at the top of the opposite open end of the outer impregnation tank; the open ends of the inner and outer impregnation tanks 1.4 are sealed with end plates 6. This device can be installed inside a large tank that can be evacuated separately, or can be operated independently, but here we will explain each part when installed in another vacuum tank 9. Explain the effect of

Vacuuming of the impregnating tank 1.4 before resin impregnation is performed through both the degassing port 5 and the resin injection port 8. Following vacuuming, an epoxy resin with low viscosity and a long pot life is injected from the resin injection port 8. At this time, the vacuum tank 9 continues to be evacuated, so that the remaining air in the glass cloth is exhausted from the upper degassing port 5. The injected resin is in space 7
At first, the liquid flows in the circumferential direction (the two flows are temporarily stopped at the lower part of the space 7. As the injected resin increases, the liquid level becomes higher and eventually reaches the edge of the glass cloth 2 at the same time around the entire circumference. After that, the resin flows into the capillary tube). Due to this action, the remaining air corresponding to the volume occupied by the resin impregnated in the height direction is pushed out from the deaeration port 5. In this way, when the resin overflows from the deaeration port 5, the impregnation ends. After this, a commonly known resin curing process begins.

According to this embodiment, if the injected resin spreads evenly in the circumferential direction in the space 7 (2) and the end plate is placed horizontally, the timing at which the resin reaches the edge of the glass cloth 2 is determined by the radius and circumference. Both directions are exactly the same. Therefore, the conditions for impregnating the glass cloth 2 with resin are the same regardless of the location. Also, since the inner and outer impregnating tanks 1.4 are in close contact with the glass cloth 2, the resin impregnation conditions are the same regardless of the location. The impregnating supply is always limited to the edge of the glass cloth 2. As a result, the difference in impregnating properties due to the difference in glass lamination direction, which was one of the major causes of void formation in the conventional vacuum impregnating method, does not become a problem.

That is, since the impregnation is performed only in the direction of the laminated surface, the possibility of voids remaining is reduced. Furthermore, since the resin is injected from below and exhausted from above, residual air to be replaced is very easily removed.

As another example, even if glass opening or glass mat is used as the reinforcing fiber, the same result can be obtained from FRP without ζ niboid.
A container is obtained. In addition to epoxy resin, polyester resin and vinyl ester resin can also be used as the impregnating resin.

〔Effect of the invention〕

According to the method of the present invention, since a gap is provided at the open end of the impregnation tank, it is possible to manufacture a PRP container without voids. A high-strength FRP container that does not allow helium to pass through can be manufactured.

[Brief explanation of the drawing]

l...Inner impregnating tank 2...Glass cloth 3...Open end 4...Outer impregnating tank 5...Deaeration port 6...
End plate 7... Nitoma 8... Resin injection port. Agent Patent Attorney Noriyuki Chika

Claims (1)

[Claims] A fibrous material layer is formed around the outer periphery of an inner mold having a lower open end, and an outer mold having a lower open end and an upper degassing port covers the outside of the fibrous material layer, and the lower parts of the inner mold and the outer mold are covered with an outer mold having a lower open end and an upper degassing port. An annular space is formed between the open ends in which the fibrous material layer does not exist, and true nitrogen is degassed from the upper deaeration port, and liquid resin is injected from the annular space into the fibrous material layer. A method for manufacturing a fiber-reinforced plastic container.