JP2010213511A - Protective sheet for communication cable, method for manufacturing the same and communication cable with protective sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective sheet for a communication cable excellent especially in water resistance, a method for manufacturing the protective sheet and the communication cable with the protective sheet. <P>SOLUTION: The protective sheet 100 for the communication cable includes a sheet body 10 having laminates 8 provided on both surfaces of a heat-insulating layer 1, respectively. In the protective sheet 100 for the communication cable, the laminates 8 are arranged on the heat-insulating layer 1, and include: air shut-off layers 2 containing metallic layers 4; cotton layers 5 arranged on the air shut-off layers 2; and flame-retardant layers 6 disposed on the cotton layers 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protective sheet for a communication cable, a manufacturing method thereof, and a communication cable with a protective sheet.

  A communication cable including an optical fiber cable and a metal cable is wired from a telephone station to a subscriber's house via a so-called tunnel (cable tunnel) installed underground. For this reason, when a fire occurs in a cave, the damage is very large (Non-Patent Document 1). Therefore, the communication cable installed in the cave is wound around a protective sheet, and the communication cable with the protective sheet is In general, it is supported by a plurality of cable brackets installed at regular intervals along the length of the road.

  As such a communication cable protective sheet, for example, a cover sheet (Patent Document 1) in which metal foil and reinforcing cloth are provided on both surfaces of a heat insulating layer, or a non-combustible heat insulating material made of carbon fiber and metal fiber, respectively. A disaster prevention sheet (Patent Document 2) formed from a composite woven fabric obtained by laminating a cloth and an aluminum foil is known.

Japanese Utility Model Publication No. 61-162236 JP-A-62-221375

NTT East, “The biggest communication disaster in history-lessons from telephone cable fire”, [online], [searched on December 24, 2008], Internet <URL: http://www.ntt-east.co.jp/ theater / collection.html>

  However, although the protective sheets described in Patent Documents 1 and 2 described above have sufficient fire resistance to protect from fire, there is room for improvement in terms of other characteristics.

  That is, in the cave, it is actually possible that water that has penetrated the ground dripped from the ceiling and this water contacts the protective sheet. In this case, since the protective sheet described in Patent Documents 1 and 2 does not have sufficient water resistance, the water is absorbed by the protective sheet, and the protective sheet is increased in its own weight and is bent, and communication is performed accordingly. The cable may also be bent. And when this bending becomes excessive due to the absorption of water over a long period of time, there is a risk that the transmission characteristics of the communication cable will deteriorate.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication cable protection sheet excellent in water resistance, a manufacturing method thereof, and a communication cable with a protection sheet.

  As a result of intensive studies to solve the above problems, the present inventors have surprisingly arranged a metal layer and a flame retardant layer sequentially from both sides of the heat insulating layer on both sides of the heat insulating layer, and the metal layer and the flame retardant layer. In the meantime, it has been found that the above problem can be solved by arranging a cotton cloth which is generally excellent in water absorption, and the present invention has been completed.

  That is, the present invention is provided with a sheet body formed by providing a laminate on both sides of the heat insulating layer, and the laminate is (1) a ventilation barrier layer disposed on the heat insulating layer and including a metal layer; (2) A protective sheet for a communication cable, comprising: a cotton cloth layer disposed on the air-permeable barrier layer; and (3) a flame retardant layer disposed on the cotton cloth layer.

  This protective sheet for communication cable is particularly excellent in water resistance. For this reason, when the protective sheet for the communication cable is wound around the communication cable and the communication cable with the protective sheet is supported by cable brackets installed at regular intervals along the length direction of the cave, the following effects are obtained. can get.

  That is, even if water that has penetrated the ground drops from the ceiling and comes into contact with either the inner or outer laminated body of the protective sheet, the laminated body sufficiently prevents water absorption. For this reason, the increase in the weight of a protection sheet is fully suppressed and the bending of a communication cable can fully be suppressed. Therefore, according to the protective sheet of the present invention, it is possible to sufficiently suppress the deterioration of transmission characteristics in the communication cable.

  Furthermore, the protective sheet of the present invention has not only a flame retardant layer but also a heat insulating layer. For this reason, the protective sheet of the present invention can sufficiently prevent the communication cable from reaching a high temperature state even when the outer side of the protective sheet becomes hot due to the occurrence of a fire while being wound around the communication cable. . Furthermore, since the protective sheet of the present invention also has a ventilation blocking layer, it is possible to sufficiently prevent the flame from reaching the communication cable even in the event of a fire.

  In the laminated body, it is preferable that the cotton cloth layer is disposed in a non-adhered state on the ventilation blocking layer. In this case, the flexibility of the protective sheet is increased as compared with the case where the cotton cloth layer is disposed in an adhesive state on the ventilation blocking layer. For this reason, the operation | work at the time of winding a protection sheet around a communication cable becomes easy.

  The present invention also includes a sheet body manufacturing process in which a laminate is formed on both sides of the heat insulation layer to form a sheet body, and the laminate is (1) an air flow disposed on the heat insulation layer and including a metal layer. A protective sheet for a communication cable, comprising: a barrier layer; (2) a cotton cloth layer disposed on the ventilation barrier layer; and (3) a flame retardant layer disposed on the cotton layer. Is the method.

  According to this manufacturing method, it is possible to obtain a communication cable protection sheet that is particularly excellent in water resistance.

  Furthermore, this invention is a communication cable with a protective sheet formed by winding the protective sheet for communication cables mentioned above around a communication cable.

  ADVANTAGE OF THE INVENTION According to this invention, the protection sheet for communication cables excellent in water resistance especially, the manufacturing method, and the communication cable with a protection sheet are provided.

It is a top view which shows one Embodiment of the protection sheet for communication cables which concerns on this invention. It is sectional drawing along the II-II line of FIG. It is a front view showing one embodiment of a communication cable with a protection sheet concerning the present invention. It is a figure which shows 1 process of the manufacturing method of the protection sheet for cables which concerns on this invention. It is a figure which shows the other process of the manufacturing method of the protection sheet for cables which concerns on this invention. 3 is a graph showing the results of a water resistance test for the protective sheet of Example 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

(Protective sheet for communication cable)
1 is a plan view showing a preferred embodiment of a protective sheet for a communication cable according to the present invention, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is for the communication cable in FIG. It is a front view which shows the communication cable with a protection sheet formed by winding a protection sheet around a communication cable.

  As shown in FIG. 1, a communication cable protection sheet (hereinafter simply referred to as “protection sheet”) 100 according to the present embodiment is attached to a sheet body 10 and one surface 10 a of the sheet body 10. And two sheet fasteners 14 fastened in a wound state. The seat fastener 14 includes, for example, a flame resistant belt 12 that is fixed to one surface 10 a of the seat body 10, and a metal fitting 13 that is attached to one end of the belt 12. The metal fitting 13 can hold the sheet main body 10 in a wound state by hooking and pulling out the other end of the belt 12, for example.

  As shown in FIG. 2, the sheet main body 10 includes a heat insulating layer 1 and laminated bodies 8 provided on both surfaces of the heat insulating layer 1. The laminated body 8 is disposed on the heat insulating layer 1 and includes a ventilation blocking layer 2 including the resin layer 3 and the metal layer 4, and a laminated sheet 7 disposed on the ventilation blocking layer 2. The laminated sheet 7 is composed of a cotton cloth layer 5 disposed on the ventilation blocking layer 2 and a flame retardant layer 6 disposed on the cotton cloth layer 5. The ventilation blocking layer 2 blocks ventilation and prevents a flame from reaching the communication cable even in the event of a fire.

  Here, the flame retardant layer 6 is disposed on the cotton fabric layer 5 in an adhesive state. Further, the cotton fabric layer 5 is disposed on the ventilation blocking layer 2 in a non-adhesive state. And the laminated body 8, the heat insulation layer 1, and the laminated body 8 are integrated by sewing using the thread | yarn 11 for sewing.

  According to this protective sheet 100, as shown in FIG. 3, first, the sheet body 10 is wound around the communication cable C, and the other end of the belt 12 is hooked and pulled out to the metal fitting 13 attached to one end of the belt 12. The wound sheet body 10 is fastened. The communication cable 200 with the protective sheet obtained in this way is placed on the cable bracket 30 installed at regular intervals along the length of the sinus. Here, the cable bracket 30 is a rod-shaped member that protrudes from the wall surface of the cave.

  At this time, as for the protective sheet 100, the laminated body 8 is excellent in water resistance especially. For this reason, even if the water which has penetrated into the ground drops from the ceiling and comes into contact with the outside of the protective sheet 100, the laminated body 8 sufficiently prevents water absorption. Moreover, even if water contacts the laminated body 8 inside the protective sheet 100, the laminated body 8 sufficiently prevents water from being absorbed. For this reason, the increase in the weight of the protective sheet 100 is sufficiently suppressed, and the bending of the protective sheet 100, in particular, the bending of the portion of the protective sheet 100 that is not supported by the cable bracket 30 is sufficiently suppressed. As a result, the bending of the communication cable C is sufficiently suppressed. Therefore, according to the protective sheet 100, the deterioration of the transmission characteristics in the communication cable C can be sufficiently suppressed.

  Further, the protective sheet 100 has sufficient shear resistance and wear resistance in practical use. For this reason, even if it is stepped on by mistake by an operator or the bending of the protective sheet 100 becomes excessive, the protective sheet 100 is difficult to tear due to the shearing force applied to the protective sheet 100 at that time. Further, even in an environment where the protective sheets 100 rub against each other at the time of cable laying work or after laying, a hole or the like hardly occurs due to wear force. Due to these characteristics, water can be sufficiently prevented from entering the protective sheet 100.

  Furthermore, the protective sheet 100 has not only the flame retardant layer 6 but also the heat insulating layer 1. For this reason, even if the protective sheet 100 is wound around the communication cable C and the outside of the protective sheet 100 becomes hot due to the occurrence of a fire, the communication cable C can be sufficiently prevented from becoming a high temperature state. it can. Furthermore, since the protective sheet 100 also has the ventilation blocking layer 2, it is possible to sufficiently prevent the flame from reaching the communication cable C even in the event of a fire.

  In the protective sheet 100, the cotton fabric layer 5 is disposed on the ventilation barrier layer 2 in a non-adhered state. For this reason, the softness | flexibility of the protection sheet 100 increases compared with the case where the cotton fabric layer 5 is arrange | positioned on the ventilation | gas_flowing interruption | blocking layer 2 in the adhesive state. For this reason, the operation | work at the time of winding the protection sheet 100 around the communication cable C becomes easy.

  Next, the heat insulating layer 1, the ventilation blocking layer 2, the cotton cloth layer 5, and the flame retardant layer 6 constituting the sheet body 10 will be described in more detail.

(Insulation layer)
The material constituting the heat insulating layer 1 may be any material as long as it has a heat insulating property, and is preferably a flame retardant from the viewpoint of protecting the communication cable C from high heat at the time of fire. As the flame retardant, for example, ceramic fibers such as carbon fibers, metal fibers, and alumina fibers can be used. Among these, carbon fiber is particularly preferable. This is because the flame resistance is excellent. Specifically, Pyromex (registered trademark) felt # 300HS is used as the carbon fiber.

  Carbon fibers and metal fibers have flexibility. For this reason, when carbon fiber or metal fiber is used as the material constituting the heat insulating layer 1, there is no damage due to load or scattering of the material unlike conventional ceramic materials, and the safety is high.

  The thickness of the heat insulating layer 1 is not particularly limited, but is preferably 2.0 to 10.0 mm from the viewpoint of flexibility of the protective sheet 100 and protection of the communication cable C from fire.

(Vent blocking layer)
The ventilation block 2 includes the metal layer 4 as described above. The ventilation blocking layer 2 is composed of, for example, a resin layer 3 and a metal layer 4. The resin constituting the resin layer 3 is not particularly limited as long as it is a resin, and examples of such a resin include polyethylene terephthalate, nylon, and polyimide. In particular, polyethylene terephthalate is preferable from the viewpoint of high strength and flexibility.

  Examples of the metal layer 4 include aluminum foil, stainless steel foil, and copper foil. Among these, aluminum foil is preferably used in terms of weight reduction and thermal conductivity. The thickness of the metal layer 4 is not particularly limited, but usually 0.01 to 0.20 mm is preferable. Furthermore, 0.03-0.06 mm is preferable.

(Cotton fabric layer)
The cotton fabric layer is composed of cotton fibers. The thickness of the cotton fabric layer 5 is not particularly limited, but is usually 0.1 to 0.5 mm, and more preferably 0.2 to 0.4 mm from the viewpoint of strength and weight reduction.

(Flame retardant layer)
The material constituting the flame retardant layer 6 may be any material having flame retardancy, and examples of such a material include chloroprene rubber, silicone rubber, or fluorine rubber containing a flame retardant. In particular, silicone rubber is preferable because it is halogen-free. The thickness of the flame retardant layer 6 is not particularly limited, but is usually 0.03 to 0.30 mm, and preferably 0.03 to 0.10 mm from the viewpoint of fire resistance and weight reduction.

(Manufacturing method of communication cable protection sheet)
Next, the manufacturing method of the protection sheet 100 is demonstrated with reference to FIG.4 and FIG.5.

  FIG. 4 is a diagram showing one process of the manufacturing method of the protective sheet of FIG. 1, and FIG. 5 is a diagram showing another process of the manufacturing method of the protective sheet of FIG.

  First, the laminated body 8 is formed on both surfaces of the heat insulating layer 1 to form the sheet body 10 (sheet body manufacturing process).

  For this purpose, as shown in FIG. 4, one heat insulating layer 1, two air blocking layers 2 and two laminated sheets 7 are prepared.

  As the ventilation blocking layer 2, a laminate of the resin layer 3 and the metal layer 4 is prepared.

  The laminated sheet 7 can be prepared by laminating the flame retardant layer 6 on the surface of the cotton fabric layer 5. For example, when the flame retardant layer 6 is composed of a silicone rubber containing a flame retardant, a vulcanizing agent is added to the silicone compound that is the raw material of the silicone rubber, and the viscosity is adjusted to, for example, 200 to 400 dPa · s with a solvent. Then, after defoaming to obtain silicon paste, the laminated sheet 7 can be obtained by applying the silicon paste to the cotton cloth layer 5 and curing it in a drying furnace. As the silicone compound, for example, SH502U A / B manufactured by Toray Dow Corning Silicone Co., Ltd. can be used. In addition, as the solvent, an organic solvent such as toluene can be used. The temperature of the drying furnace may be any temperature that can cure the silicone paste, and is, for example, 150 to 170 ° C.

  Next, the ventilation blocking layer 2 and the laminated sheet 7 are overlapped so that the ventilation blocking layer 2 and the laminated sheet 7 are sequentially disposed on both sides of the heat insulating layer 1, respectively. That is, the laminated sheet 7, the ventilation blocking layer 2, the heat insulating layer 1, the ventilation blocking layer 2 and the laminated sheet 7 are superposed in this order.

  Then, as shown in FIG. 5, the laminated sheet 7, the ventilation barrier layer 2, the heat insulating layer 1, the ventilation barrier layer 2, and the laminated sheet 7 are integrated by sewing using a sewing thread 11. In this way, the sheet body 10 is obtained.

  Then, two seat fasteners 14 are prepared, and the belt 12 of the sheet fastener 14 is attached to the one surface 10 a side of the seat body 10 by sewing using, for example, a thread similar to the thread 11. Thus, the production of the protective sheet 100 is completed.

(Communication cable with protective sheet)
The communication cable 200 with the protective sheet can be obtained by winding the sheet main body 10 of the protective sheet 100 around the communication cable C and fastening the sheet main body 10 in a wound state with the sheet fastener 14.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the cotton cloth layer 5 is disposed on the ventilation barrier layer 2 in a non-adhered state. However, the cotton cloth layer 5 may be disposed on the ventilation barrier layer 2 in an adhesive state. The communication cable C is not particularly limited. Examples of the communication cable C include an optical fiber cable and a metal cable.

  Moreover, in the said embodiment, although the sheet | seat fastener 14 is fixed to the one surface 10a side of the sheet | seat main body 10, and it is integrated with the sheet | seat main body 10, it may be a different body from the sheet | seat main body 10. In this case, the protective sheet 100 is composed only of the sheet main body 10. Even in this case, the sheet body 10 can be fastened by winding and tying a string member having flame resistance.

  Furthermore, in the said embodiment, although the ventilation block 2 is comprised by the laminated body of the resin layer 3 and the metal layer 4, the resin layer 3 is omissible. In this case, the ventilation blocking layer 2 is composed of only the metal layer 4.

  Next, the content of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
(Configuration of protective sheet: Laminated sheet (flame retardant layer / cotton fabric layer) / ventilation barrier layer / heat insulation layer / ventilation barrier layer / laminate sheet (flame retardant layer / cotton fabric layer)
First, a heat insulating layer, a ventilation blocking layer and a laminated sheet (flame retardant layer / cotton fabric layer) were prepared as follows.

  As the heat insulating layer, felt-like carbon fiber (Pyromex felt # 300HS manufactured by Toho Tenax Co., Ltd.) was prepared.

  As the ventilation blocking layer, a laminate of a PET film having a thickness of 12 μm and an aluminum foil having a thickness of 30 μm was prepared.

  The laminated sheet was prepared as follows. First, 3.5 parts by mass of a vulcanizing agent is added to 100 parts by mass of a flame-retardant silicone compound (SH502U A / B manufactured by Toray Dow Corning Silicone Co., Ltd.), dissolved in toluene, and a viscosity of 200 to 400 dPa · s. After defoaming, defoaming was performed to obtain a silicone paste. Thereafter, this silicone paste is applied to a cotton cloth having a thickness of 320 μm with a knife over roll coater, dried in a continuous drying furnace, vulcanized and cured at 150 to 170 ° C., and a silicone rubber having a thickness of 30 to 100 μm. A flame retardant layer consisting of the above was formed on a cotton cloth to prepare a laminated sheet.

  Next, one heat insulation layer prepared as described above, two ventilation barrier layers, and two laminated sheets are laminated sheets (flame retardant layer / cotton cloth layer) / ventilation barrier layer / heat insulation layer / ventilation barrier. Layers / laminated sheets (flame retardant layer / cotton layer) were laminated.

  And this was integrated by sewing using the thread | yarn for sewing, and the sheet | seat main body was obtained.

  On the other hand, two sheet fasteners each having a metal fitting (single wire feed) attached to one end of a belt having a layer configuration of laminated sheet / ventilation blocking layer / laminated sheet were prepared. In addition, the same thing as Example 1 was respectively used as a lamination sheet and a ventilation blockage layer.

  And the center part of the belt was sewn using the thread | yarn for sewing. Thus, a protective sheet was obtained.

(Comparative Example 1)
(Configuration of protective sheet: flame retardant layer / ventilation barrier layer / heat insulation layer / ventilation barrier layer / flame retardant layer)
A protective sheet was obtained in the same manner as in Example 1 except that no cotton cloth was used.

(Comparative Example 2)
(Configuration of protective sheet: Laminate (flame retardant layer / ventilation barrier layer) / Heat insulation layer / Laminate (flame retardant layer / ventilation barrier layer)
First, a 6 mm ceramic blanket was prepared as a heat insulating layer.

  Next, 1.4 parts by mass of the curing agent was added to 100 parts by mass of the acrylic pressure-sensitive adhesive. Then, the acrylic adhesive added with the curing agent is applied to a glass cloth having a thickness of 170 μm with a floating knife coater and dried at 100 ° C. in a continuous drying furnace, and the adhesive layer having a thickness of 10 μm is formed on the glass cloth. Got on. In this way, two flame retardant layers made of a glass cloth with an adhesive layer were prepared.

  Next, the pressure-sensitive adhesive layer was coated in the same manner as described above on the surface opposite to the surface coated with the pressure-sensitive adhesive layer in the flame retardant layer prepared as described above.

  Next, an aluminum foil of 20 μm was bonded onto one pressure-sensitive adhesive layer of the glass cloth in which the pressure-sensitive adhesive layer was coated on both sides. Thus, two laminates (flame retardant layer / ventilation barrier layer) composed of the flame retardant layer and the ventilation barrier layer were obtained.

  Then, one heat insulating layer and two laminated bodies were laminated in the following manner: laminated body (flame retardant layer / ventilation barrier layer) / thermal insulating layer / laminate body (flame retardant layer / ventilation barrier layer).

  Next, this was sewn in the same manner as in Example 1 except that a glass yarn coated with a fluororesin was used to obtain a sheet body.

  A sheet fastener was attached to the sheet body in the same manner as in Example 1 except that a corrugated metal fitting was used as a metal fitting and a glass yarn coated with a fluororesin was used to obtain a protective sheet.

  The protective sheets obtained in Example 1, Comparative Example 1 and Comparative Example 2 were evaluated for water resistance, shear resistance, fire resistance and abrasion resistance as follows.

[Evaluation of water resistance]
Each protective sheet is submerged for 3 days, taken out, left in a room temperature environment, and the weight of the protective sheet in the initial stage (before submersion), 3 days after immersion (extraction date), 1 day after the extraction date, and 3 days after the extraction date Was measured. The results are shown in Table 1 and FIG.

  As shown in Table 1 and FIG. 6, the protective sheet of Example 1 was found to have a very small weight change rate due to submersion and extremely excellent water resistance as compared with the protective sheets of Comparative Examples 1 and 2.

[Shear resistance]
For the shear resistance, a laminate of each protective sheet was cut into a size of 200 mm × 50 mm, and a test sample with a cut length of 100 mm was prepared. Test method-Part 4: Tear test It evaluated by performing the tear test based on JISK6404-4444: 1999 trouser method. The results are shown in Table 2. In Table 2, the greater the force required for tearing, the better the shear resistance.

As shown in Table 2, the force required for tearing was significantly greater in the laminate of Example 1 than in the laminate of Comparative Example 1. Moreover, although the force required for tearing of the laminated body of Example 1 was small compared with the laminated body of the comparative example 2, it has confirmed that it was a value sufficient in practical use.

[Fire resistance]
About fire resistance, it evaluated as follows. That is, a protective sheet is cut into a size of 200 mm × 200 mm to prepare a test sample. This test sample is wound around a communication cable having a length of 250 mm, and both ends of the test sample are flame-impregnated with silicon having a width of 10 mm × length of 25 mm. It was fastened so as not to come off with fibers. The test sample was then contacted with a burner flame. At this time, the part of the test sample that is in contact with the flame is a part that is wound around the communication cable, the height of the flame coming out of the burner tip is 100 mm, and the distance from the burner tip to the test sample is 70 mm. The contact temperature between the flame and the test sample was about 890 ° C. And the rod-shaped thermometer was inserted in the center part of the sample which is inside a test sample and contacts a flame, and the temperature after 20 minutes was measured. The results are shown in Table 3.

As shown in Table 3, the protective sheets of Example 1, Comparative Example 1, and Comparative Example 2 all had a temperature of 400 ° C. or less after 20 minutes, and were found to have excellent fire resistance.

[Abrasion resistance]
The abrasion resistance was evaluated by conducting an abrasion test based on “Rubber Pulling / Plastic Pulling Test Method—Part 3: Tensile Test JISK6404-22 Abrasion Resistance Test”. In the wear test, the wear amount and the wear ratio were measured for each rotation speed. The results are shown in Table 4. In Table 4, the smaller the wear amount and wear ratio, the better the wear resistance. In the wear test, the number of revolutions of the test piece, the load applied to the wear wheel, and the wear wheel were as follows.
Test piece rotation speed: 60 rpm
Load applied to worn wheels: 500 g (500 g × number of worn wheels (2) = 1000 g)
Wear wheel: H18

上記結果より、実施例１の保護シートは、比較例２の保護シートに比べて、耐摩耗性の点で十分に優れるものであった。また実施例１の保護シートは、比較例１の保護シートに比べると耐摩耗性の点では同等であったが、実使用上十分な耐摩耗性を有することが確認できた。 As a result of the abrasion test, in the protective sheets of Example 1 and Comparative Example 1, even when the number of rotations of the wear wheel was 600 or more, the portion polished by the wear wheel was only the flame retardant layer on the surface. On the other hand, in the protective sheet of Comparative Example 2, the aluminum foil was exposed when the number of rotations of the wear wheel reached 600 or more.

From the above results, the protective sheet of Example 1 was sufficiently superior in terms of abrasion resistance as compared with the protective sheet of Comparative Example 2. Further, the protective sheet of Example 1 was equivalent in terms of abrasion resistance as compared with the protective sheet of Comparative Example 1, but it was confirmed that the protective sheet had sufficient abrasion resistance in actual use.

  As mentioned above, it was confirmed that the protective sheet for communication cables of the present invention is particularly excellent in water resistance.

  DESCRIPTION OF SYMBOLS 1 ... Heat insulation layer, 2 ... Air-permeable blockage layer, 3 ... Resin layer, 4 ... Metal layer, 5 ... Cotton cloth layer, 6 ... Flame-resistant layer, 7 ... Laminated sheet, 8 ... Laminated body, 10 ... Sheet body, 11 ... Yarn , 12 ... belt, 13 ... metal fitting, 14 ... sheet fastener, 30 ... cable bracket, 100 ... protective sheet, 200 ... communication cable with protective sheet.

Claims (4)

It has a sheet body with a laminate on each side of the heat insulation layer.
The laminate is
(1) a ventilation blocking layer disposed on the heat insulating layer and including a metal layer;
(2) a cotton cloth layer disposed on the ventilation barrier layer;
(3) having a flame retardant layer disposed on the cotton fabric layer;
A protective sheet for communication cables.   The protective sheet for a communication cable according to claim 1, wherein in the laminate, the cotton cloth layer is disposed in a non-adhered state on the ventilation blocking layer. Including a sheet body manufacturing process for forming a sheet body by forming a laminate on both sides of the heat insulation layer,
The laminate is
(1) a ventilation blocking layer disposed on the heat insulating layer and including a metal layer;
(2) a cotton cloth layer disposed on the ventilation barrier layer;
(3) having a flame retardant layer disposed on the cotton fabric layer;
A method for manufacturing a protective sheet for a communication cable, characterized by the above. A communication cable with a protective sheet obtained by winding the communication cable protective sheet according to claim 1 or 2 around the communication cable.

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