JP3172602B2 - Method of manufacturing colored cable for suspended structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cable for a suspended structure,
For example, the present invention relates to a method for manufacturing a colored cable in which a polyolefin resin layer and a colored fluorine-based resin layer are bonded via an adhesive as a sheath or an anticorrosion layer of cables such as a cable-stayed bridge cable and a suspension bridge hanger cable.

[0002]

2. Description of the Related Art Conventionally, a polyolefin resin represented by polyethylene or polypropylene has been widely used for a sheath or an anticorrosion layer of a cable. However, when the polyolefin resin is used in a place exposed to direct sunlight due to poor weather resistance, the polyolefin resin contains carbon and has a black color with improved weather resistance. Therefore, in order to meet the demand for colored cables that place importance on the surrounding environment and aesthetics, the colored fluororesin is further extruded and coated.
Layered structures have been proposed and put into practical use.

[0003] Fluorine-based resins are used in a wide range of applications because of their excellent weather resistance, chemical resistance, solvent resistance, non-adhesion and flame retardancy. However, the fluororesin in the two-layer structure is intended to be colored and is extremely expensive compared to the polyolefin resin. Therefore, even if the thickness of the colored layer is small, there is no problem in weather resistance. This is economically advantageous.

[0004] On the other hand, fluorine-based resins have the disadvantage of poor adhesion to various substrates and non-adhesion to polyolefin resins due to their non-adhesiveness. Accordingly, if the fluorine-based resin layer is too thin, peeling due to wrinkles or external damage when bending is likely to occur.

[0005] As a countermeasure for this, a method is considered in which the polyolefin resin and the fluorine-based resin layer are bonded and integrated with an adhesive to prevent wrinkles and peeling. As an adhesive for bonding a polyolefin resin and a fluorine-based resin, a primer composition for a fluorine-based resin (for example, see JP-A-4-24-2).
No. 0538).

[0006]

However, even if this adhesive is applied to a polyolefin resin and the fluororesin is extrusion-coated thereon, a satisfactory adhesive strength cannot be obtained by itself. was there.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a new method of manufacturing a colored cable which is economical and hardly causes wrinkles and peeling of a colored fluororesin layer having weather resistance and the like. I do.

[0008]

According to the present invention, a colored cable has a double-extrusion coating layer structure of a polyolefin resin layer and a colored fluorine resin layer as an outermost sheath or an anticorrosion layer, and an adhesive between them. In a cable having a structure in which a polyolefin resin layer and a fluororesin layer are bonded using a fluororesin primer composition, before or after applying an adhesive on the polyolefin resin layer, the surface of the polyolefin resin layer is heated, and the surface temperature is increased. A method for producing a colored cable, characterized in that the layers are adhered by extrusion-coating a fluorine-based resin layer thereon with the film raised. Further, the present invention is a method for producing a colored cable, wherein the temperature at which the surface of the polyolefin resin layer is heated is 50 ° C. or more.

[0009]

[Function] Before extrusion coating of a fluorine-based resin layer, the surface of the polyolefin resin layer is heated to a temperature of 50 ° C. or more, and the surface temperature is raised to sufficiently draw out the original adhesive strength of the adhesive and bond the polyolefin resin. The layer and the colored fluorine-based resin layer can be satisfactorily integrated.

[0010]

The polyolefin resin used in the present invention is a homopolymer or copolymer of α-olefin such as ethylene, propylene and butene-1, or a vinyl ester containing such α-olefin as a main component (eg, vinyl acetate). ,
Unsaturated carboxylic acid (acrylic acid, maleic anhydride, etc.) or its ester (ethyl acrylate, methyl methacrylate, etc.), aromatic vinyl monomer (styrene, etc.) vinyl silane (vinyl trimethoxy silane, γ-methacryloyloxy propyl) Blocks of other unsaturated monomers such as methoxysilane), random or graft copolymers, and the like are used.

[0011] Such an olefin polymer may be blended with an inorganic filler, a colorant, various stabilizers, a conductive agent and the like as long as it can be molded.

In the present invention, even olefin polymers having no polarity are suitably used, and these can be appropriately selected from commercially available ones. Particularly, an ethylene polymer and a propylene polymer are preferable from the viewpoint of moldability.

Further, the fluororesin used in the present invention comprises:
Homopolymers or copolymers such as vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether, or these fluorine monomers and α such as ethylene and propylene -Copolymers with olefins are used.

Above all, polyvinyl fluoride and polyvinylidene fluoride, particularly polyvinylidene fluoride, are preferably used from the viewpoint of moldability and melt adhesion. Polymethyl methacrylate can be blended with polyvinylidene fluoride and used as a composition, and inorganic fillers, coloring agents, and various stabilizers can be blended and used as long as they can be molded.

In the present invention, the polymerization product A used as an adhesive comprises an olefin polymer (a) having at least one functional group in one molecule and a radical polymerizable monomer having a reactivity with this functional group. The radical polymerizable olefin B obtained by reacting the polymer (b) with the radical polymerizable olefin polymer containing an alkyl (meth) acrylate and / or a fluorine-containing unsaturated monomer as an essential component. It is a polymerization product obtained by copolymerizing a suitable monomer (c). (See JP-A-4-20538)

The heating apparatus used in the present invention includes an electric heater, a hot air dryer using the electric heater, a gas burner, a far infrared heating furnace, a hot water tank, and the like. In short, it is only necessary that the surface temperature of the polyolefin resin can be raised almost uniformly in a short time. It is more desirable if the temperature can be adjusted.

Next, a specific embodiment will be described. First,
The following experiment 1 was performed in order to examine the relationship between the surface temperature of the polyolefin resin and the adhesive strength by a sheet test.

[Experiment 1] High-density polyethylene (hereinafter referred to as HDPE) as a polyolefin resin [trade name: H
i-zex5100ESK, manufactured by Mitsui Petrochemical Co., Ltd.]
A 12 mm thick sheet piece was prepared, and an adhesive [trade name: Surfren A-1000, manufactured by Mitsubishi Yuka Co., Ltd.] was applied to this surface.
After brushing, 1 in a gear oven at a temperature of 80 ° C.
Dry for 5 minutes. On the other hand, polyvinylidene fluoride (hereinafter referred to as PVDF) is used as a fluorine resin (trade name: KYN
AR2800, manufactured by Atochem North American)
An m-thick sheet piece is prepared and heated to a temperature of 210 ° C. The surface temperature of the PVDF coated with the adhesive is raised from room temperature to 9
Prepare each of the samples changed to 0 ° C.
The VDF sheet was placed, pressed for about 9 seconds, cooled, and the peel strength between layers was measured by a tensile tester. The result is
It is shown in the table.

[0019]

[Table 1]

From these results, it can be seen that when the surface temperature of HDPE is room temperature, adhesion by an adhesive cannot be expected at all, and it is necessary to set the surface temperature of HDPE to at least about 50 to 60 ° C. under at least these conditions.

Next, the following experiment 2 was performed to confirm the adhesive strength when the surface of the polyolefin layer in the cable was not heated.

[Experiment 2] The high-density polyethylene (HDPE) shown in the above Experiment 1 was coated with a thickness of about 7.5 mm on a polyethylene-coated cable sample (outer diameter = about 100 mm), and the surface was further coated. After the adhesive shown in Example 1 was applied, the adhesive was dried in a hot air drier for about 10 minutes to remove volatile components such as an organic solvent in the adhesive, and after about 30 minutes, the above Experiment 1 was repeated. Was extrusion coated with a polyvinylidene fluoride (PVDF) having a thickness of about 3 mm. P
The temperature during VDF extrusion was about 210 ° C. Thereafter, the cable was cut into a length of about 10 cm, and a cut was made vertically in the PVDF, and the adhesiveness was confirmed. That is, a sufficient adhesive force could not be obtained by simply applying an adhesive and extruding and coating PVDF as in the case where the surface temperature of HDPE shown in Experiment 1 was room temperature.

Next, the results of a test using a cable for a cable-stayed bridge are shown in the following Experiment 3.

[Experiment 3] As shown in the cross sectional view of FIG.
After applying the adhesive shown in Experiment 1 onto 109 cable strands for cable-stayed bridge (outer diameter = about 82 mm) with 109 mmφ galvanized steel wire 1, about 1 piece of high-density polyethylene (HDPE) 2 was applied.
After coating with a thickness of 0 mm and further applying the adhesive 3 shown in Experiment 1 to the surface, two far-infrared heating cylinders (capacity 10
kW and 45 kW) at 80 ° C.
The mixture was heated to a temperature of 100 ° C., and a colored layer of polyvinylidene fluoride (PVDF) 4 similarly shown in Experiment 1 was extrusion-coated to a thickness of about 3 mm. The temperature at the time of extrusion of this PVDF4 was about 210 ° C.

Cut the above cable to a length of about 10 cm,
After extracting the contents of the steel wire, the steel wire was divided into 16 parts vertically, and a cut of about 25 mm was made between HDPE2 and PVDF4 at one end of each, and it was set on a tensile tester to measure the peel strength between layers. The result was 3.6 kgf /
Sufficient adhesive strength of not less than cm width was obtained.

[Experiment 4] Using a polyethylene-coated product having the same specifications as the cable used in Experiment 2, applying an adhesive, and adjusting the calorific value of the far-infrared heater to adjust the PVDF.
The adhesive force was measured when the polyethylene surface temperature immediately before coating was continuously changed. The extrusion temperature of the coated PVDF is about 210 ° C. and the coating thickness is 3.0 mm. Experiment 3 above
Polyethylene and PVDF using a tensile tester in the same manner as
The peel force between them was measured. The results are shown in Table 2 and the graph of FIG.

[0027]

[Table 2]

[0028]

FIG. 3 is a block diagram showing the entire line of a cable manufacturing apparatus to which the present invention is applied. That is, the polyolefin resin-coated cable 6 delivered from the drum of the cable delivery device 5 is first coated with an adhesive by an adhesive coating device 7 and then passed through a far infrared heating furnace 8 to be heated. Then, a fluorocarbon resin is extrusion-coated on the outer periphery by an extruder 9 as a colored layer, and the cable is then passed through a cooling water tank 10 to be cooled. The completed fluororesin-coated cable 11 is wound around a drum of a cable winding device 13 via a take-off track device 12.

[0030]

As described above, according to the method for producing a colored cable of the present invention, an adhesive is applied to the surface of a polyolefin resin layer, and the surface of the colored fluorine-based resin layer is heated and the temperature is raised. By extrusion-coating, it is possible to obtain a colored cable in which wrinkles and peeling are less likely to occur in the fluororesin by firmly bonding and integrating the polyolefin resin layer and the fluororesin layer. Therefore, the colored fluorine-based resin layer can be thinned, and a colored cable that is economical and has excellent weather resistance can be realized.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the surface temperature of polyethylene and the adhesive force with polyvinylidene fluoride,

FIG. 2 is a cross-sectional view showing a structure of a cable for a cable-stayed bridge to which the present invention is applied;

FIG. 3 is a line configuration diagram of a colored cable manufacturing apparatus to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Galvanized steel wire 2 Polyethylene 3 Adhesive 4 Polyvinylidene fluoride (colored layer) 5 Cable feeding drum 6 Polyolefin resin-coated cable 7 Adhesive coating device 8 Far infrared heating furnace 9 Fluorine resin extruder 10 Cooling water tank 11 Fluorine resin Completed cable 12 Take-off track 13 Cable take-up drum

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kyoji Sawasawa 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture "Inside the Hidaka Electric Wire Co., Ltd." (72) Inventor Tsutomu Sasaki Hitachi, Ibaraki Prefecture 5-1-1 Takamachi “Inside the Hidaka Factory of Hitachi Cable Co., Ltd.” (58) Field surveyed (Int. Cl. ⁷ , DB name) D07B 1/16

Claims (2)

(57) [Claims] 1. A colored cable, wherein the outermost sheath or anticorrosion layer has a double extrusion coating layer structure of a polyolefin resin layer and a colored fluororesin layer, and a primer composition for a fluororesin is used as an adhesive therebetween. Before or after applying the adhesive on the polyolefin resin layer in a cable with a structure in which the resin layer and the fluororesin layer are bonded, the surface of the polyolefin resin layer is heated, and the fluorocarbon resin A method for producing a colored cable for a suspended structure, wherein the layers are bonded by extrusion coating. 2. The method according to claim 1, wherein the temperature for heating the surface of the polyolefin resin layer is 50 ° C. or higher.