JPS6015460B2 - Method of manufacturing formed tubes - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a formed tube.

As shown in Fig. 1, a conventional molded tube is made by impregnating a base material such as glass cloth, glass roving cloth, cloth, paper, asbestos with a thermosetting resin and making it into a prepreg 2 using a mandrel 1.
A laminated product was formed by winding it in a spiral shape, and the product was heated and pressurized in molds (upper mold 3, lower mold 4) to produce a formed tube.

However, since the pressing force when wrapping the prepreg 2 is smaller than the final pressing force (compression force by the mold), the winding thickness of the prepreg 2 is determined by the final cavity of the mold (as shown in Fig. 2).
(when the mold is closed) is larger (larger in bulk). Therefore, when the mold is closed, the prepreg 2 has a shape as shown in FIG. 3, in which the burr flows out near the bartending line (seam) of the mold and at the same time, the prepreg 2 is crushed and the winding is disordered. Normally, the bartender line of the mold is provided to pass through the center of the molded product, and therefore, molded products in this manner have maximum burr outflow. After pressure forming, this burr is scraped off, resulting in a break in the continuity of the base material, which makes the formed tube easy to break if high pressure is applied inside the tube, and causes flash flashes if high voltage is applied to the creeping surface. In order to improve the above-mentioned drawbacks, research has been conducted on a method in which the mold is made into a multi-segmented structure and simultaneously shrunk in the radial direction. However, simultaneous shrinkage of multi-segmented molds is difficult, and many small burrs are dispersed and flowed out, which eliminates the above-mentioned drawbacks. I can't.

The object of the invention is to provide a method for manufacturing shaped tubes that does not have the above-mentioned disadvantages.

In the present invention, a prepreg is prepared by impregnating a nonwoven fabric mat or roping fibers aligned in one direction and a randomly oriented substance with a thermosetting resin, and a nonwoven fabric mat or a prepreg prepared by aligning them in one direction.

A laminated product is formed by wrapping fibers around a mandrel in a spiral shape with a randomly oriented material arranged on the outer periphery.
The present invention then relates to a method for manufacturing a molded tube, characterized in that the laminate is pressure-formed in a mold having a bartending line that does not pass through the center of the molded product. Randomly oriented materials used in the present invention include glass fibers, carbon fibers, cloth,
Materials such as paper and asbestos are used. In addition, these molded tubes using nonwoven mats, roving fibers aligned in one direction, and materials with random orientation are made of nonwoven mats or roving fibers aligned in one direction on the inner periphery, and random orientation on the outer periphery. shall be arranged to form a laminate. The thermosetting resins impregnated into these non-woven mats, unidirectionally aligned roving fibers, and randomly oriented substances include epoxy resins, fer/fer resins, melamine resins, unsaturated polyester resins, and urea resins. It can be used without any particular restrictions.

The molding is performed at a pressure of 10 to 200 atm, preferably 30 to 7 atm.
pressure, temperature 120-170°C, preferably 140-1
It is carried out in the range of 50 qo. Further, in the present invention, the bartending line is not particularly limited as long as it does not pass through the center of the molded product, but it is preferable to set it at a position where the radius of the molded product is ○ and the radius of the laminated product is d. . The present invention will be explained below with reference to the drawings.

FIG. 4 is a side view showing a molded tube according to an embodiment of the present invention, and FIG. 5 is a perspective view showing a state in which the molded tube of the present invention shown in FIG. 4 is manufactured.

Next, embodiments of the present invention will be described.

Unsaturated polyester resin-impregnated glass roving fibers 5 cut into predetermined lengths and aligned in one direction are placed on a mandrel 1.
A laminated product is formed by winding 19 layers of glass fibers 6 on top of each other, and further wrapping 6 layers of unsaturated polyester resin-impregnated glass fibers 6 with random orientation on top of these layers.

Next, the laminated product is inserted into a mold having a bartending line that does not pass through the center of the molded product as shown in FIG. However, if a laminate of the above-mentioned size is inserted into a mold, a gap will be created between the mold and the laminate. Therefore, when prepreg 2 corresponding to the insufficient volume is placed on the lower mold 4 in advance and the laminate is inserted onto the upper surface of the lower mold 4, the prepreg 2 is further placed on the upper surface of the laminate and pressure is applied.
Leave it so that a slight burr appears. The prepreg 2 used at this time is not particularly limited, but it is preferable to use the same prepreg as the prepreg to be finally wound. Next, the tube is heated under pressure at a pressure of 7 and a temperature of 150.degree. C., and then the mandrel 1 is extracted and machined to a predetermined size to form a formed tube. In the present invention, the prepreg 2 is interposed above and below the laminate to form the product, but the method is not necessarily limited to this method. The molded tube of the present invention is a nonwoven fabric mat or a pre-reg formed by impregnating roping fibers aligned in one direction and a randomly oriented substance with a thermosetting resin. A laminate is formed by winding the fibers on the inner periphery and a randomly oriented substance on the outer periphery in a spiral shape around a mandrel. By pressure forming with a mold, the continuity of the laminated fibers due to burr flowing out from the bartender line can be reduced.In the conventional method, one layer of prepreg has a thickness of about 0.2 sails, and when wrapped in 25 layers, the continuity of the laminated fibers is reduced by 5. Layer approx. 1. However, according to the present invention, the continuity break occurs in only one layer.

In addition, the conventional model with the same size and internal pressure resistance was barely 200k9/ground (broken at the bartender line),
According to the present invention, it is possible to obtain a molded product that can withstand up to 700k9' and does not cause flashover even if a high voltage is applied to the creeping surface.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a method for manufacturing a subordinate molded product, Fig. 2 is a front view showing a state in which a laminate is inserted into a conventional mold, and Fig. 3 is a conventional mold shown in Fig. 2. Fig. 4 is a front view showing a molded product according to an embodiment of the present invention, and Fig. 5 is a front view showing a molded product before being manufactured and machined. It is a perspective view showing a state. Explanation of symbols, 1...Mandrel, 2...
・Prepreg, 3...upper mold, 4...lower mold,
5...Unsaturated polyester resin-impregnated glass roving fiber, 6... Randomly oriented unsaturated polyester resin-impregnated glass fiber.藷 l zu shou 2 kei 3 zu ro 4 zu s

Claims (1)

[Claims] 1 A nonwoven mat or a prepreg made by impregnating roving fibers aligned in one direction and a randomly oriented substance with a thermosetting resin, or a prepreg made by impregnating roving fibers aligned in one direction with random roving fibers aligned in one direction on the inner periphery. A laminate is formed by disposing a oriented material on the outer periphery and spirally wrapping it around a mandrel, and the laminate is then pressure-formed in a mold with a parting line that does not pass through the center of the molded product. A method for manufacturing a formed tube, characterized by: