JPS61175017A - Manufacture of corrugated pipe of polyimide - Google Patents

Abstract

PURPOSE:To mold a polyimide pipe body rich in flexibility, by molding a laminate pipe having an intermediate layer consisting of thin metal strips or the like capable of being deformed plastically and polyimide tapes that are wound helically in such a manner that the pipe may be corrugated. CONSTITUTION:A metal strip 1, polyimide tapes 2, 3 and a metal strip 4 in the stated order with the metal strip 1 innermost are inserted between cantilevered mandrel 11 and an endless belt 12 wound around the mandrel 11 and driven by driving rollers 13, 13' and are wound helically around the mandrel 11 to be formed into a tubular body while the strips and the tapes are being fed, so that a laminate pipe (P) having an inner layer 5, an intermediate layer 6 and an outer layer 7 is molded. Since the metal strips 1, 4 and the polyimide tapes 2, 3 are wound with their opposed surfaces not being subjected to joining treatment, the inner and outer layers 5, 7 and the intermediate layer 6 are not united. Rollers each having a groove are pressed against the inner and outer surfaces of the laminate pipe (P) that has left the tip of the mandrel 11, so that the pipe is plastically deformed and corrugated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a polyimide corrugated tube in which the longitudinal section of the tube wall is formed into a corrugated shape to provide good flexibility.

(Prior Art) Conventionally, polyimide tubes having excellent heat resistance have been produced by applying a heat-fusible resin to one side of a polyimide film, as proposed in JP-A-51-19071, for example. After laminating them and winding them spirally around a heat-resistant core,
It is molded by heating to fuse the polyimide film and a resin having heat-fusible properties, and then removing the core after cooling.

(Problems to be Solved by the Invention) However, the polyimide tube formed by the above method has smooth inner and outer surfaces, has poor flexibility due to the hardness of the tube material itself, and has a small radius of curvature. Because it is difficult to bend, it cannot be used in applications that require great flexibility.

(Means for Solving the Problems) The present invention aims to solve the above problems and provide a new manufacturing method capable of molding a highly flexible polyimide tube. is a polyimide tape consisting of an inner and outer layer formed by spirally winding a plastically deformable strip of thin metal or the like, and a polyimide tape coated on at least one side with a resin having a lower melting point than polyimide between the inner and outer layers. and an intermediate layer formed by laminating this polyimide tape, forming a laminated tube into a corrugated shape, and thermally fusing the laminated polyimide tape by heating. , a method for producing a polyimide corrugated tube comprising the step of peeling and removing the inner and outer layers from the laminated tube which has been shaped into a corrugated shape.

(Example) An embodiment of the present invention will be described below.

Figure 1 shows the forming process of a laminated pipe opening formed by spirally winding a metal strip such as aluminum foil and a polyimide tape.
A metal strip (1),
The polyimide tape (21! 31) and the metal strip (4) are sequentially inserted from the inside, and while these are spirally wound on the mandrel αD to form a tubular body, the inner layer is rotated and advanced on the mandrel αυ. (5) A laminated pipe η having an intermediate layer (6) and an outer layer (7) is formed.

At this time, the polyimide tape (
2) (31) is coated with a resin having a relatively high melting point on both sides, or coated with the above coating on one side, and is laminated and wound so that the coating layers are in contact with each other. has been done.

In addition, metal strips (1) (4) and polyimide tape (2)
1 (31) is wound without any adhesive treatment applied to its opposing surfaces, and the inner and outer layers (5) (7) and the intermediate layer (6) are not bonded.

Note that the forming of the laminated tube side is not limited to the above embodiments; instead of the metal strip, a strip made of other plastically deformable material may be used, or the tube body may be formed by winding the strip in a spiral shape. Alternatively, the intermediate layer (6) may be formed by forming one polyimide tape instead of winding and laminating a plurality of polyimide tapes.
The laminated intermediate wall may be formed by fully polymerizing adjacent side edges of two sheets of wide polyimide tape and winding them in a spiral shape.

Fig. 2 shows a state in which the wall of the laminated pipe (2) formed as described above is shaped into a spiral or annular waveform in the longitudinal section.
The process of giving a shape to this waveform is performed by, for example, using the mandrel α.
The metal strips (1) (4) forming the inner and outer tubes (51 (7)) are rotated forward on the mandrel 0υ and pressed against the inner and outer surfaces of the laminated pipe opening leaving the tip of the mandrel 0υ.
) is plastically deformed into an uneven shape with the intermediate layer (6) sandwiched between them, but other known means capable of shaping the pipe wall into a corrugated shape may also be used.

Moreover, this process of forming a shape may be performed continuously with the laminated tube forming process as described above, or may be performed discontinuously.

The laminated tubes with corrugated tube walls as described above are cut into regular lengths and placed in a heating furnace at 270 to 310°C, and the laminated polyimide tape (21(3)) is applied to the coating layer. Intermediate layer (6) by heat-sealing
to integrate.

Note that this heating step may be performed continuously with the corrugated stacked tube by advancing it through a heating furnace installed in front.

The laminated tube that has undergone the heating process as described above is cooled, and then changes from the intermediate layer (6) to the inner and outer layers (6) which are not bonded to the intermediate layer (6).
The metal strips (1) and (4) of 51 (7) are peeled off and removed (as shown in Figure 3, a corrugated tube made only of polyimide that has been plastically deformed into a corrugated state) is removed. (1
) is obtained.

In addition, in the above-mentioned example, the case where the laminated tube forming process, the forming process, the heating process, and the inner and outer layer peeling process are performed in these orders is shown, but the order is not limited to the above. (b) Laminated pipe forming process - heating process - forming process - inner and outer layer peeling process; (b) laminated pipe forming process - forming process - forming process - inner and outer layer peeling process - heating process. A corrugated tube equivalent to the example is formed.

(Operations and Effects of the Invention) As explained above, according to the present invention, the pipe wall made of polyimide, which is difficult to melt mold, unlike general thermoplastic resins, is plastically deformed into an uneven shape together with the inner and outer layers. It can be formed into a corrugated shape, giving excellent flexibility and stretchability to polyimide tubes that lack flexibility, making polyimide tubes suitable for various uses that require good flexibility. It has come to be widely used and has great industrial value.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the forming process of the laminated pipe of the present invention, Fig. 2
The figure is a side view of a laminated tube showing a state in which the corrugations are formed, and FIG. 3 is a side view of a polyimide corrugated tube. fl) (41...metal strip, (2) (3)
... Polyimide tape, (5) ... Inner layer,
(6)...middle layer, (7)...outer layer,
■...Laminated pipe, (1)...Polyimide corrugated pipe.

Claims (1)

[Claims] An inner and outer layer formed by spirally winding a plastically deformable strip of thin metal or the like, and a polyimide tape having at least one side coated with a resin having a lower melting point than polyimide is wound between the inner and outer layers in a spiral shape. A step of forming a laminated tube consisting of an intermediate layer formed by laminating this polyimide tape, a step of giving the laminated tube a corrugated shape, a step of heat-sealing the laminated polyimide tape by heating, and a step of forming a corrugated tube. A method for manufacturing a polyimide corrugated tube, comprising the step of peeling off and removing inner and outer layers from the laminated tube that has been dented.