JPS6231450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate sheath in which a metal tape and an adhesive are laminated, and a sheath material is adhered thereon.

In general, laminate sheaths have excellent moisture resistance and mechanical strength, and are used, for example, insulated wire cores of various electric wires and cables, products that coat the core material of transportation pipes, etc., and products that do not have a core material. For example, it is used for sheaths of various products such as heat medium transport pipes and elliptical waveguides.

Hereinafter, the present invention will be explained using the case of manufacturing a laminate sheathed cable, which is a typical example of these, but the present invention is not limited thereto.

What is generally called a laminate sheath cable has a structure as shown in FIG. 1 as an example. In the figure, 2 is an insulated wire core (hereinafter abbreviated as core) of power cables, communication cables, etc., which is a conductor covered with an insulator, or a collection of multiple wires thereof. , on which a metal shield, binding, etc. are applied.

On top of the core 2, a tape 5 (hereinafter abbreviated as laminated tape), which is a metal tape 3 (e.g. aluminum tape) laminated with an adhesive 4 (e.g. ethylene copolymer) on one or both sides, is placed in the shape of a pipe. A plastic sheath 7 made of polyethylene (PE), polyvinyl chloride (PVC), etc. is covered on top of the overlapping part 6 by heating, and a laminated tape 5 is formed. A laminated sheathed cable 1 is formed by adhering them.

In order to manufacture such a laminated sheath cable, a method as shown in FIG. 2 has conventionally been used.

In the figure, at the same time that the core 2 is continuously fed out from the supply reel 8, the laminate tape 5 is supplied from the supply stand 9 to the outer periphery of the core 2 in a longitudinally attached state, and enters the molding machine 10. Molding machine 1
0 covers a core 2 by forming a laminate tape 5 into a pipe shape, and consists of a plurality of forming rolls or forming dies 11. After the pipe is coated, it is heated by the preheater 12 to bond the overlapping portion 6 (FIG. 1) of the laminate tape 5, and immediately while being evacuated by the vacuum device 13,
The sheath 7 is extruded and coated using a sheath extruder 14 to form a laminate sheathed cable 15, cooled through a water cooling tank 16, and then wound onto a winder (not shown) or the like.

However, the laminated sheath manufactured by this method has a problem in the overlapping part 6 of the tapes, as shown in the sheath structure shown in FIG. Furthermore, a step 18 is also formed on the outer surface of the sheath 7, and this has the disadvantage that when the cable is subjected to an impact at low temperatures, it may break from this portion. Further, the laminate tape 5 used in this method is a coil-wound product manufactured in a separate process, and the most common method for manufacturing it is, for example, rolling an adhesive onto an aluminum tape using a calendar roll.
At this time, in order to uniformly cover the thin adhesive and ensure sufficient adhesion between the aluminum tape and the adhesive,
This method requires large manufacturing equipment and manufacturing technology including advanced quality control, resulting in high costs.

In addition, there are quality issues such as the tapes blocking each other during storage because they are manufactured and stored in the form of laminated tapes, and the adhesive strength decreasing due to changes in the surface condition of the aluminum tapes. However, there was a drawback that the type of adhesive used had to be carefully selected.

The present invention was made to solve the above-mentioned problems, and attempts to simultaneously form a laminate tape in the sheath coating process by using a single aluminum tape instead of the conventional laminate tape.
The present invention aims to provide a method for manufacturing a laminate sheath that is significantly cheaper from the viewpoint of energy saving than conventional methods.

Another object of the present invention is to continuously coat the surface of a metal tape in a method in which there is a concern that the adhesive strength between the metal tape and adhesive (laminate resin) will decrease compared to when conventional laminated tapes are used. The improvement is achieved by roughening the surface, and by filling the stepped portion of the overlapping portion of the metal tape with an adhesive to eliminate voids in the overlapping portion and preferably also completely bond the tapes at the overlapping portion. To provide a method for easily manufacturing a laminate sheath with good airtightness and excellent mechanical strength in one step by smoothing.

Another object of the present invention is that since a single metal (aluminum) tape is supplied and used, an ordinary cold welder can be used as is for connecting the tapes, which is extremely useful in the continuous production of long products. It is an object of the present invention to provide a method for manufacturing a laminate sheath that is advantageous and suitable for cases where electrical conductivity at the connection of an external conductor is essential, such as for example in a laminate sheathed coaxial cable for cable broadcast television (CATV).

In the present invention, when a metal tape is continuously supplied to a molding machine and formed into a pipe shape, the surface of the metal tape is continuously roughened, and then the metal tape is transferred to a molding die in which an adhesive is held in a fluid state. coating the adhesive onto the roughened metal tape by passing it through;
This method of manufacturing a laminate sheath is characterized in that a sheath material is immediately extruded and coated thereon.

The metal tape used in the present invention is aluminum, copper or an alloy thereof, stainless steel,
It is made of metal such as lead, and is particularly suitable for soft metal tapes such as softened aluminum tapes.

In the present invention, to roughen the surface of these metal tapes, ordinary surface roughening techniques such as grinding with a whetstone can be used before preforming, but a preferred method is to roughen the surface of these metal tapes when forming them into a pipe shape. This method uses a molding machine to continuously roughen the tape surface at the same time as molding. The simplest method is to use a tape forming jig (roll or die) in the forming machine made of a material that is at least harder than the metal tape. Only the surface of the tape (pipe) on the side that comes into contact with the ingredients is appropriately roughened.

Note that the surface of the forming jig that comes into contact with the tape can be roughened to some extent even if it is smooth depending on the materials of the jig and the tape, but it is preferable to roughen the surface appropriately.

Hereinafter, the present invention will be explained by examples using the drawings. FIG. 4 is a diagram illustrating an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 2 indicate the same parts.

In the figure, a cable core 2 and a metal tape, such as a soft aluminum tape 19, are supplied to a forming machine 25 in a longitudinally oriented state. The molding machine 25 is equipped with a molding die 11 made of, for example, hard copper.
The tape 19 is continuously preformed into a pipe shape so that both ends overlap. If no lubricant is used during this molding, a pipe can be obtained in which only the surface of the soft aluminum tape in contact with the surface of the hard copper molding die 11 is appropriately roughened.

Next, this pipe is cut into at least one die (hereinafter referred to as
(abbreviated as drawing die) 26. The figure shows an example in which this die 26 is installed just before the crosshead of the sheath extruder 14, and the adhesive 27 is kept in a fluid state in the drawing die 26.
For example, it is supplied by an adhesive extrusion device 28. The aluminum tape 19 whose surface has been roughened by the forming die 11 and has been preliminarily formed into a pipe shape is passed through the drawing die 26 to form an adhesive 27.
is coated on the aluminum tape 19 and also filled in the stepped portion 24 of the overlapping portion of the aluminum tape 19 and the mutually overlapping portion 23 of the tapes (FIG. 6), and the pipe forming is completed. 29 is a preheating machine that preheats the aluminum tape 19 after preforming it. Thereafter, a sheath extruder 14 is immediately placed on top of the sheath extruder 14.
A plastic sheath 7 is extruded and coated by a crosshead, and cooled appropriately by a water cooling bath 16.
A laminated sheathed cable 20 according to the present invention is formed.

What is important here is the behavior at the drawing die 26, which is schematically shown in FIG. In the figure,
Foreign matter 22 such as metal debris generated during roughening is attached to the pipe 21 whose tape surface is roughened at the same time as it is formed by the forming die 11 (Fig. 4). When the adhesive 27 is run through the drawing die 26 holding the adhesive 27, an index flow is generated in the adhesive 27. On the other hand, a force acts at the entrance part (tapered part) of the drawing die 26 to block this index flow, so that the adhesive 27 27 flows as shown by the arrow. As a result, the foreign matter 22 on the pipe 21 is peeled off by the adhesive 27 and mixed into the adhesive 27, so that
There are almost no foreign substances such as metal chips on the pipe 21 after exiting the drawing die 26.

On the other hand, since the adhesive is pressed onto the roughened portion of the surface of the tape 19, it bites into the roughened surface, and as a result, the pipe 21 and the adhesive 27 are firmly bonded. Therefore, according to the present invention, even contaminants on the tape surface due to contamination from machine oil during rolling and cutting of the metal tape, dirt and dust during storage of the tape, etc. can be removed without troublesome treatment such as solvent cleaning. It can be removed without any damage.

However, from the above explanation, there is a concern that if a large amount of foreign matter such as metal chips is mixed into the adhesive 27, it will be impossible to uniformly apply the adhesive 27 with the drawing die 26, and the tape The adhesive force between the tape 19 and the adhesive 27 may decrease, but in order to prevent this, the adhesive 27 is supplied to the drawing die in excess of the amount coated on the tape (actual amount). It is sufficient to constantly overflow from the drawing die 26 to dilute the concentration of foreign matter in the adhesive 27.

The laminate sheathed cable according to the present invention obtained by this method has a sheath structure as shown in FIG. 6 as an example. In the figure, aluminum tape 1
The surface of 9 (adhesive side) is roughened, and adhesive 27 is firmly bonded thereon.

In addition, the stepped portions 14 of the overlapping portions of the aluminum tapes 19 and the mutually overlapping portions 23 of the tapes are filled with an adhesive 27 for proper adhesion, and in particular, the adhesive 27 is filled near the end surface of the upper tape 19. , there are no voids. At the same time, the upper surface of the aluminum tape 19 and the sheath 7 are completely bonded via the adhesive 27, so that the metal tape 19, the adhesive 27, and the sheath 7 are completely integrated, and the sheath 7 The appearance is also uniform without being affected by the overlapping parts of the tape. Therefore, this laminate sheath has good airtightness, excellent water-tightness, and strong mechanical strength, and has extremely superior properties compared to the cable made by the conventional method shown in FIG.

In addition, there is no need for electrical continuity between the aluminum tapes at the overlapped portions 23 of the tapes, and in the case of cables where moisture resistance is particularly important, if the overlapped portions 23 are also filled with the adhesive 27 at the same time, the mechanical strength of the overlapped portions can be improved. Further improvements in strength and moisture resistance can be achieved.

Example A laminated sheath coaxial cable was manufactured by the method of the present invention as shown in FIG.

Foamed polyethylene insulation as core, outer diameter 7.5mm
A soft aluminum tape with a thickness of 0.15 mm and a width of 29 mm was used as the metal tape. First, a pipe forming die made of hard copper is installed as the forming die 11 of the forming machine 25, and the outer diameter is
After preforming to 9.5mm, the aluminum tape is preheated to 100℃ using preheater 29, and then drawn using drawing die 2 with a hole size of 7.8mm.
6 and coated with Himilan 1652 manufactured by Mitsui Petrochemicals Co., Ltd. as an adhesive while overflowing from the drawing die 26. Here, the temperature of the drawing die section containing the adhesive was approximately 200°C. On top of this, low density polyethylene is added using a 65mm sheath extruder at approximately 200℃.
The sheath was applied using the draw-down method. Here, the degree of vacuum was set to 20 mmHg.

The cross-sectional state of the obtained laminated sheath coaxial cable according to the present invention is as shown in FIG.
The adhesive was completely filled up to the stepped portions of the overlapping portions of the metal tapes and the overlapping portions of the tapes, and there was no problem in terms of appearance.

In addition, we conducted a 180° peel test, in which the bonded aluminum tape and polyethylene sheath were pulled 180° in opposite directions, or the aluminum tape at the overlapped part of the aluminum tape was pulled 180° in the opposite direction, and the adhesive strength was measured. Between the sheaths
The adhesive strength is 4.2Kg/cm (width), and the distance between the aluminum tapes at the overlapped portion is 3.8Kg/cm (width). It was completely comparable.

In the above explanation, the method of the present invention was mainly explained for manufacturing a laminate sheath of a laminate sheath cable, but the present invention is not limited to this, and can be applied to other core materials such as transportation pipes, etc. It can also be applied to the production of products with a laminated sheath, or products with a coreless laminate sheath in which the pipe-shaped metal tape itself serves as a heat-insulating pipe for a heat medium, an elliptical waveguide, etc.

As described above, in the method of the present invention, when a metal tape is continuously fed to a molding machine and molded into a pipe shape, the surface of the metal tape is roughened, and then the adhesive is kept in a fluid state. The adhesive is coated on the roughened metal tape by passing it through a molding die (drawing die), and the adhesive is filled into at least the stepped portion of the overlapping portion of the metal tape, and then a plastic is immediately applied thereon. Since the sheath is extruded and coated, the adhesive is press-fitted into the roughened surface of the metal tape, the stepped part of the overlapped part, and the vicinity of the overlapped part of the tapes by the index flow caused by the running of the preformed metal tape in the drawing die section. Since the adhesive filling amount and coating thickness are not affected by the amount of sheath extrusion, there are no gaps in the overlapped area of the metal tape, and the adhesion between the metal tape and sheath is perfect, resulting in good airtightness. , good water impermeability,
Moreover, compared to the conventional method using a laminate tape, there is an advantage that a laminate sheathed cable having comparable adhesive strength and excellent mechanical strength can be easily produced.

In addition, the method of the present invention does not require the production of a laminate tape in a separate process, and the production of the laminate tape (coating the adhesive onto the metal tape) and the extrusion coating of the plastic sheath can be performed continuously in one process. The adhesive is coated with the adhesive by the traction flow caused by the running of the metal tape (pipe), so if, for example, the sheath extrusion is interrupted and the running is stopped, the traction flow will not work immediately and there will be no excess adhesive on the pipe. Since no coating is performed and there is no need to adjust the coating conditions of the coating agent using a drawing die, it has the advantage of being extremely easy to manufacture and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of the structure of a laminate sheathed cable. FIG. 2 is a diagram illustrating a conventional method, and FIG. 3 is a cross-sectional view showing a laminate sheath portion of a cable obtained by the method shown in FIG. 2. FIG. 4 is a diagram illustrating an embodiment of the method of the present invention, and FIG. 5 is an enlarged sectional view of the drawing die portion shown in FIG. 4. FIG. 6 is a cross-sectional view showing the laminate sheath portion of the cable obtained by the method shown in FIG. 4. 1, 15, 20... Laminated sheath cable, 2... Insulated wire core (core), 3... Metal tape, 4, 27... Adhesive, 5... Laminated tape, 6, 23... Overlapping portion, 7 ...Sheath, 8...
...Supply reel, 9...Supply stand, 1
0,25... Molding machine, 11... Molding die, 1
2, 29...Preheating machine, 13...Vacuum pulling device, 1
4...Sheath extruder, 16...Water cooling tank, 17,2
4... Step portion, 18... Step, 19... Aluminum tape, 21... Pipe, 22... Foreign matter, 26... Shaping (drawing) die, 28... Adhesive extrusion device.

Claims (1)

[Claims] 1. When a metal tape is continuously fed to a molding machine and formed into a pipe shape, the surface of the metal tape is continuously roughened, and then the adhesive is kept in a fluid state inside. A method for producing a laminate sheath, comprising coating the roughened metal tape with the adhesive by passing it through a forming die, and immediately extruding and coating the sheath material thereon. 2. The method for manufacturing a laminate sheath according to claim 1, wherein pipe forming is performed on an insulated wire core of a cable. 3. The laminate sheath according to claim 1 or 2, wherein the molding machine is equipped with a preforming jig made of at least a harder material than the metal tape, and the surface roughening is performed by the preforming jig. Production method.